The International Steam Pages


Firing a Condensing Steam Locomotive, 1991

This article is the story of the very last run of SAR 25C 3511 the last condenser in service in 1991, as told by the fireman Richard Niven in 2006.

"By the time I was based in Kimberley only no 3511 was still in original condition, all others having been converted to normal class 25NCs (non condenser). 3511 was no longer used in regular traffic and was now more of a museum piece used only on steam specials etc. I was desperate to have a go at firing this mighty beast but as I was not passed on this machine I was simply not allowed. Every time I saw her in steam I would ask the foreman if I could be trained on firing her but the answer was always "no, we don't have enough firemen to work the regular trains".

Years went by and I simply just accepted that I would never get the chance to fire this mighty condensing beast but all was not lost. On 10th May 1991 John and myself had just signed off after a trip to De Aar on our regular engine 3488. It was then we were told that we were to work train 2416 next day to De Aar and were on duty at 03h46 and that we would be using the condenser.

Both of us were well pleased with that news but after all the times we had asked to be passed out on this machine and now itís simply just thrown at us we were very reluctant to take her. We started questioning the foreman and saying such things like "we aren't passed to work on that loco" and we would get a answer like "just go do your job, I'm sure you two can work it out between you both". Lucky for me John still had his paperwork regarding the condensers from his firing days at De Aar. The whole night I sat reading these notes and took in as much as I could about this advanced machine. The whole night I was excited and looking forward to the next day on the condenser but as I was to find out I still had a few lessons to learn regarding this machine without upsetting the driver.

Next morning we arrive on duty well ahead of our booked time and find 3511 standing under the water column in front of the shed. I climb aboard and my first impression is that things do not look good. The steam pressure is way down at 60psi and only a tiny bit of red can be seen in the almost dead fire. Like any other steam locomotive I simply open the blower valve hard to draw the fire and then start the mechanical stoker. I leave it all running for a while as I get the oil and grease ready for John to lubricate the motion. By the time I am finished getting John's stuff ready the stoker has been feeding fresh coal into the firebox for about 7 minutes. I know there is enough fresh coal in the firebox to get the fire going and raise steam. Quick inspection into the firebox before I start cleaning the cab and not a single bit of red can be seen. I start cleaning the cab front and within minutes I notice the steam pressure coming up very quickly indeed. Another inspection in the box finds the fire burning white hot over the whole grate. One thing I did notice was the unbelievable pull on the fire caused by the exhaust fan in the smokebox. I have never seen any steam locomotive with such a strong blower before.

Another quick feed of coal from the mechanical stoker and the steam gauge is heading towards the red mark. I turn down the blower and continue cleaning the cab when suddenly I hear John shouting my name. "Richard--- Richard---, what the f#'/#k are you doing?" I look around but cannot see John anywhere. Just then a rather angry driver arrives from behind the tender "did you let those bloody safety valves blow of?, you just about killed me". John was furious at me. What had happened was that the silent safety valves had started to blow. Unlike any other steam loco the steam from the safety valves escapes down a pipe and is then fed to the condensing tender. This force then starts up the huge condensing fans and John had been inside the tender greasing the fans when they started. That was lesson number one--don't let the safety valves blow when driver is inside the tender.

After my first bollocking I thought I better do my best and clean the cab from top to bottom and then surprise John by making him a cup of tea before leaving shed.

Once back in the cab I look at the two controls that operate the pumps and turn the top spindle open and hope that one of the pumps starts up. Sure enough it did. As the water from the tender is hot these locomotives were not fitted with injectors but were instead fitted with turbine pumps. Each pump had a pressure gauge situated alongside the stoker gauges. The book said the operating pressure for these pumps was 150psi. I set the pump to this pressure but after 10min of running the boiler water level had only risen very slightly so I turned the pressure up to full boiler pressure and the water started to rise. This brought the boiler pressure down and as time was running out I decided to leave the fire as is and fill my tender. I done my usual and climbed up the front of the tender and on over the coal only to suddenly remember this is a condenser and it has very large fans on the roof of the tender. Do I walk over these fans? I ask myself. I decide not to and return to the cab then using the ladder at the rear of the tender climb up to the filling hole right at the back of the tender. From the top I can see the flicker of Johns paraffin lamp still inside the tender. I know I must be very careful not to let the water overflow otherwise I really will be in the s'/;t.

I watch the tank slowly fill and am just about to shut it off when I hear another angry cry from John. "Turn off that bloody water". Mad rush and I am turning the water valve off as fast as I can. Just then a very wet and angry John emerges from the door at the rear of the tender. "Just look at me now" he shouts. "The tank wasn't full" I reply. "It wonít get full, its overflow runs into the inner tender". Now I knew I really was in trouble. Two bollocking in 10 minutes is not a good start to the day on any steam loco and we haven't even left shed yet---time to make some tea!!

With all preparation complete its time to leave shed but something is still on my mind. Due to all the rush and trying to do too much in too little time I haven't filled my boiler fully. As we start to reverse I quickly turn on supply to each pump to max, open the blower and start up the mechanical stoker. John is either keeping quiet about the low water or has not yet noticed it. I know he will stop at the exit to the shed and want to blowdown the boiler and if the boiler is not full it may well lead to bollocking number 3. Oh no, come on boiler "fill up". With the stoker shut I leave both pumps running and climb down from the footplate and run ahead changing points as I go. As 3511 approaches the blowdown towers I climb aboard only to find the boiler about ĺ full. Itís no good leaving the pumps running during boiler blowdown so I quickly turn off both pumps and leave the footplate to phone out shed and also phone the shunters.

Once John has blown the boiler down he reverses up towards the stop board and I climb aboard as he passes. John has already got the pumps running as a green light is given from the shunter. We draw back further and then get sent down the "loco road" towards Alex yard. The loco road was unusual in that it was more like a double track mainline running through the yards. It was used for light engine ovements from one yard to the other. It was electrified but had no signals and was controlled from shunters at each end of the line. Sometimes engine after engine would be sent along it one after the other with no signals between., although drivers would always be told if there was another engine in the section ahead. Once up in Alex yard we couple onto a very long container train consisting of 40 wagons fully loaded. It is here in the yard that John explains some of the controls regarding the condenser to me.

On the tender are a few gauges that are important to control the tender correctly. Most important is the condensate tank level gauge (CTLG). This gauge has 3 different colours on it, namely green, red and white. The condensate tank is the return tank that sits between the bogies below the tender floor. This is where any steam that has been condensed ends up. Like any steam machine 3511 has a few steam leaks and so this condensate tank level will fall and needs filling up at regular intervals. This will be shown when the when the CTLG falls out of green and into red level. Once this happens the fireman has to take action. Right behind the fireman's seat located at the front of the tender is a large brass spindle listed "fresh water supply". By opening this valve water is fed from the main fresh water tank and into the condensate tank. Once the gauge is high up in the green the valve must be closed to stop any water running out the overflow and being wasted.

Another gauge on the tender is the temperature of the supply water to the pumps. As one would think, the hotter the feed water the more efficient and better steaming the loco would be but that's not always the case as I was to find out later.

One can adjust the water temp by moving the large ratchet type lever again situated on the tender front behind the fireman. While sitting in the yard I turn on one of the pumps only to find it is not working. John having had a few turns on condensers in the past knows exactly what is wrong. The pumps are fitted with a overheat trip and this has tripped. One can reset it easily by climbing down the steps and simply pushing a button situated on the side of the pump. Once this is done the pump starts up. With boiler full, steam at red mark and a good fire we get the green light and head for De Aar. As we pull out the yard and onto the main it all seems very strange to me. Working a steam locomotive without a beat is really weird. I keep wanting to shut off the stoker as though we were drifting downhill. Next thing I notice is the amount of smoke this machine makes. I set the stoker to its slowest but still loads of black smoke is pouring out of her chimney. For John it is also quite difficult. As this locomotive has no beat one must listen to the rather silent beats in the exhaust pipe leading to the tender to set the cut-off. Not an easy task if the mechanical stoker is running as it makes a lot of noise. As we head out the yard and across the points at Beaconsfield South box and onto the De Aar mainline I call out to John "green" and hold two fingers up to indicate. With the exhaust fan turning at hi speed the fire is now burning white hot and all looks like we are in for a great journey----if only.

As we head along the flats towards Spytfontein 3511 has the load flying along at about 80kph. I set the mechanical stoker as slow as it will go and try to be as efficient as possible at firing the engine. With one pump running and stoker set at slow the steam pressure appears to like to sit at 210psi. But one pump is not sufficient to keep the boiler water level constant and so I need to make a plan. By turning the stoker up faster the steam slowly increases towards the red mark and then I can start the next pump. This may fill the boiler slightly but with two pumps running the steam pressure quickly returns to 210psi and even less if left too long. Once it has fallen it is time to turn off the no 1 pump and give it a rest and start again at getting the steam up to red mark. It appeared strange that the boiler pressure seemed to like sitting at 210psi. It would remain there constantly until the regulator was closed and then rush up to the red mark and then fall back to 210psi as soon as the regulator was opened. We later discovered that the safety valves were set slightly low and were blowing off early. Of course with them feeding into a pipe we could not hear or see them when they blew off.

As we head down the steep bank towards Modder River itís both heads out the windows looking ahead to see the signals. On seeing the distant signal at green I shout across to John "green, two off" and immediately start up the stoker for the long climb ahead. We thunder through Modder River on our "Silent Susie" at about 80kph. As usual on any steam locomotive I keep my eyes rotating to all parts of the engine that concern my job, smoke, water gauge, steam, stoker and on the condenser the condensate gauge.

As we head over the Modder River bridge I notice the smoke at the chimney has stopped indicating either the stoker has stopped or has run dry of coal. On inspection I notice the front of the tender is empty and itís time to pull a slide to allow the coal further back to fall into the stoker trough. Once that's done I open the stoker up to full speed in order to get the coal through to the firebox as soon as possible. It starts feeding coal into the box but only a rather light grey smoke appears at the chimney. "Oh no, is my fire dead" I ask myself. Quick inspection of the fire finds it burning white hot but something is not right in that box. We continue onwards up the bank towards Heuningnesskloof but 3511 is no longer performing like she was. Another inspection into the firebox reveals the truth. The fire is a rather dark colour with loads of blue flame indicating masses of clinker. As we head through Heuningnesskloof a strong side wind is getting up and is beginning to take hold of the train. John is having to work 3511 harder than usual to keep the train going. We approach the lower section of Enslin bank doing about 45kph. My clinkered up fire is making things difficult for me at keeping steam and water in the boiler. Instead of using both pumps now and again itís down to one pump now and again. I have to work very carefully now to get us over the summit without letting the water get too low. The main cause of all this is the old coal in the tender that has been sitting there for the last six months and is more like stones rather than coal. By the time we reach Enslin summit we are down to about 25kph and my fire looks more like a massive lump of tar.

We head over the summit and with regulator shut I have the smokebox fan going its fastest to get my steam and water back into the boiler. I am tempted to give the fire a shake or break up the clinker with the irons but with the gale blowing like it is there would be a very big chance of starting a veld fire. I decide to pack the sides and front of the box using the shovel. As there is only a few more miles of pulling before the downhill to Orange River this should be ok.

As we approach Graaspan John asks if I'm ok to proceed. "Yes" I reply and he opens the regulator. Normally any train would have been flying down this bank into Graaspan but again this gale force wind is holding back the train.

By the time John shuts off near Belmont steam is well down and just to make things worse my no 1 pump has tripped out. With blower on hard and no 2 pump running not much is happening in 3511's boiler. The fire is simply a lump and refuses to burn. Even on the downhill towards Witput the train is getting slower and slower due to the strong side on wind. With no chance of getting any steam out of this fire I have to take the chance and use the fire irons. But even with these I cannot break this solid lump of clinker. On that note we decide to use the shaker. With only about half a glass of water showing itís not good but we must try something or we will be stranded before long. Unlike injector fed locomotives where the ashpan coolers (water jets) are operated from the injectors the condenser simply uses a large water valve situated just above the firebox door on the back of the boiler. With the cooler on I start shaking the fire. The whole box jumps up and down and not much happens but at least the sides are now open and some air can get up the sides of the box. I turn on the stoker and try to keep as much coal away from the middle of the box as possible. With the sides burning the steam rises towards red mark and I switch no 2 pump on. As we approach Witput signals indicate two off and we are now clear into the next section before Orange River. With the boiler now back to normal John opens the regulator on the downhill section simply to gain some speed. The whole Karroo is now just a dust storm and we struggle to see ahead of the train.

With our water stop at Orange River not far off I start to prepare for fire cleaning etc. One most important thing for me is to remove the steam supply pipe to the shaker handle and pour some valve oil (steam oil) into it. This will lubricate the handle and also the shaker cylinders making the shaker work much better. At Orange River it is not normally required to oil and grease a 25/25NC but since 3511 has been standing for the last 6 months I know John will want to do a complete inspection and re grease and oil of the motion. As we approach Orange River I roll another fire into the box and open the ashpan cooler and both drop grates. As the 25's water filling hole on the tender is different from a ordinary NC the marks on the ground will not locate the correct stopping point for John and its left to me to give John hand signals to stop correctly from the ground.

With the water set slowly its over the top of the fans, down the coals and into the cam in a mad rush. Enthusiasts are watching our every move. Some start asking questions but I simply ignore them. There's nothing worse when youíre busy and trying to concentrate and someone stands there asking questions.

With cooler on I start shaking the fire bars but not much is happening except that the whole lump of clinker is jumping up and down. Pricker, 12ft rake and it is giving me a hard time, the clinker just will not break. I leave the fire bars set at a angle and try to lift the solid clinker up but this just bends the fire iron, its hell. Just then one of the enthusiasts shouts "water, water's running over". Through the coals and across the fans again then back to the cab in a flash. After about 30min I manage to break up this solid 3ft thick lump of clinker.

With all clinker out and a new red bed on the grate I start up the stoker. Grey smoke immediately appears at the chimney. Out to the ashpan I start to rake out the clinkers and ash into the pit below the engine. Into the cab and another fire is loaded. I then untangle the spray pipe to wash out the last ashes in the ashpan. The spray pipe is worked from no 1 pump. I turn on the pump but the gauge simply races up to the same pressure as the boiler pressure. It's then I remember that no 1 pump has tripped. Out of the cab, reset pump, back into cab, start up the pump then down to the ashpan with the spray pipe. Through the cab out to the other side and everything has become a mad rush.

By the time I have refilled the tender and got everything back to normal we have overstayed our stop by 20min. Goods trains are allowed 20min and passenger trains only 15 for servicing at Orange River and we have now been here for just over 40min. All this time John has been out inspecting and lubricating the engine and looking for any faults that may have occurred along the way. After the mad rush and all back to normal we whistle up for the road. With signal pulled we gently leave the station loop and again head for De Aar and into a massive dust storm.

As we head out the River and up the bank 3511 is performing well but I know that once that terrible coal sets in it will be another long drawn out struggle. Once up the bank from Orange River the line is rather flat through some flood lands as far as Kraankuil station from where the dreaded climb up Rooidam bank begins. Normally the driver can ease off the regulator on the flats but again with the dreadful side on wind John has to keep 3511 working very hard. As if there is not enough to keep the fireman busy one has to keep a close watch on the condensate tank level gauge situated on the tender. If it falls out of the green position one has to open the small valve behind the fireman's seat on the tender front and let water in from the fresh water tank. Left open too long and it will waste water out the overflow. Let the tank go down too far and the pumps will trip out.

As we head through Kraankuil at about 50kph the once white flames of the fire are beginning to turn to blue indicating yet more clinker build-up. As we head up the bank I try my best to fire as slow as possible and keep the clinker to a minimum. I'm now getting into the full swing of things and getting use to this condensing machine. Only thing I haven't tried yet is the condensate temperature handle feeding the water supply to the pumps. It has been set at low temp all the way but with so much more going on in the cab I just decide to leave it well alone for the time being.

On up the bank and poor 3511 is struggling against the bank and the side on wind to keep the train moving. My side of things is not too good either. The fire is slowly becoming a solid lump of clinker again and I'm forced to let the water go down in order to maintain steam pressure.

As we head over Rooidam summit my steam pressure is up at her usual 210psi but my water level is way down at ľ of a glass. Itís now make up time on the short downward section to Poupan. With blower on hard and both pumps running I get as much water into the boiler before the next climb ahead.

As we approach Poupan I switch off both pumps and start up the stoker. John winds the reverser back to 35% and opens the regulator slowly.

With the engine working hard and the stoker feeding the fire I expect smoke to appear at the chimney any time now but nothing is happening. Another inspection into the firebox reveals what has happened. On the downhill to Poupan I let the clinker get too cold and it has all hardened up into a solid rock. I know itís going to be a struggle all the way to De Aar now.

As we climb the short bank I again have to sacrifice the water in order to maintain full boiler pressure. Once over the summit its downhill for about 2km to Potfontein and then the real climb begins, the dreaded bank from Spytfontein to Bhershoek summit. A distance of about 35km. Itís not a really steep bank but just seems to go on forever and with the wind blowing side on it does not help. Once over the top and heading down the bank, I'm hoping to get stopped at Potfontein and get my fire sorted out. No such luck today and both outer home and distant signal are showing green as we approach Potfontein.

Itís now going to be very difficult maintaining steam up this next section. With the water already down at half a glass there is not much more water left to sacrifice for steam. Speed is now down to about 30kph and John is doing his best to keep the train moving against this terrible side on gale.

Half way between Potfontein and the next station Houtkraal we pass a old water tank that must have been used in the old days for locos with much smaller tenders. At this point I things in the boiler are not looking good. My steam is sitting at 210psi and if that gets any lower the train will come to a stand. To make matters worse my water level is now down to about 1/3 of a glass and its now I decide to try something different.

The condensate water feed handle has been set at low temp all the way so far all the way since Kimberley, and itís now test time. Surely the hotter the water going into the boiler the better it would steam --- or one would think so! I move the handle to a much higher temp position. Immediately I notice the pumps steam gauge heads up towards the same as boiler pressure but I leave it set to hi. With the handle set to high the boiler pressure starts rising and I think I have cracked it with 3511 but I soon realized I hadn't. With the feed to the pumps set up so high it was mainly just steam and very little water that was being fed into the pump and this soon caused no 1 pump over speed and trip. Also at this temp most of the water coming out from the condensate tank would just about be wet steam and so nothing would be getting through into the boiler anyway. With steam at 210psi and water way down at just under ľ glass I move the handle more towards the cooler side again and start up no 2 pump. The boiler pressure immediately starts falling and now I just do not have enough water left in the boiler to sacrifice it anymore for steam.

As we head on towards Houtkraal I just have to do my best. With water so low I just have to let the steam start to fall slowly. On approach to Houtkraal signals I'm so busy in the cab trying to keep us on the go when John shouts out "Yellow, one off--loop". What a relief this is for us! John shuts the regulator and I immediately put on the blower but the water is now very low in the boiler and is just showing at the bottom of the glass. With only no 2 pump working I am rather worried. I have heard stories of firemen climbing down the cab steps and resetting the pumps while on the move. Dare I try 
this? I ask myself.

I know I was often a "daredevil" at times but this time I think common sense took first place.

Once at a stand in the loop I reset pump no 1 and immediately get stuck into cleaning the fire. John is again outside checking over the engine. With only about another 8km to Bhershoek summit I am not too worried about giving the fire much of a clean. So long as I have a full boiler on leaving Houtkraal I will be happy. Itís now time for me to join the others outside with my camera although not many good shots will be had today due to the terrible dust storms.

After letting a passenger train past the signal is pulled for us and we head up the last section of the bank towards Bhershoek. Knowing that itís all downhill from there I just keep the boiler pressure up full and sacrifice the water all the way to the summit. Once over the top its almost all downhill for the next 30km into De Aar. At De Aar we approach the red signal slowly and watch as the large yellow light comes on below the signal indicating "goods or siding". John opens the regulator for the short but very steep climb up into the yard. As we approach the yard a green flag is given from the shunter telling us to enter the yard. Once into the yard and uncoupled from the load of containers its off to the loco shed for a well earned break.

After arriving at De Aar loco shed we draw alongside the coal loading grab. The main coal stage no longer being used thanks to coal thieves and vandals. I start by getting the fire irons down from the tender and try my best at breaking up some of the massive lumps of clinker in the firebox. it's a mighty task but so long as I can get some air through the grate 3511 should make some steam on the newly loaded coal. As soon as the first load of coal lands inside the bunker I immediately start up the mechanical stoker and turn the blower on hard. Within seconds wonderful dark black smoke appears from the chimney. What a difference in colour from that horrible stuff from Kimberley. I knew now we were on a winning turn. I kept the stoker going, loading as much good coal into the box as possible as the old horrible stuff had all turned to clinker and tar so hopefully this new coal would make fire cleaning much easier. Once the tender was full we move off forward past the coal stage and on up to the triangle. I run ahead of the loco changing points as required then once turned John brings 3511 to a stand over the water filled ashpits.

Again I start by pouring oil down the steam pipe to lubricate the rocking grates cylinders and then start shaking the fire. As before the fire is just a maze of hard lumps of clinker but at least the new De Aar coal is burning and making it much easier than what I had at Orange River. While I clean out the firebox John is outside cleaning the ashpan using the ashpan pricker.

Fifteen minutes later and we are all done at the ashpits and then back off down towards the coal stage to refill the fresh water tank in the tender. With the water column set very slow John and myself decide to give the boiler and smoke deflectors a wipe down using the usual so called "railway polish". This is simply a mixture of paraffin and oil mixed into a large piece of cotton waste. Once all has been wiped down it is then polished up with a dry piece of waste. It is also very rewarding.

Once the engine is cleaned it is time for a bite to eat. While John goes around lubricating the motion I fry up two massive rump steaks together with a few other nice bits of food on the shovel. Then another cup of tea from my stainless steel billy can and a 5 minute rest before the tender starts to overflow.

With boiler and tender full we slowly head forward towards the exit road where we stop. I quickly run across to the shed office and get our back working train number as well as the most important thing of the day "chocolate and coke". This is my energy for the return trip and will most possibly be finished within 10km of leaving De Aar. After a quick stop at the blowdown chimneys and instructions from the shunter we head off to the yard to pick-up our load. As we run alongside the yard we pass two diesels heading towards the shed with ex-steam driver Captain Deedriks driving from the rear cab of the 2nd diesel. We later found out that those diesels were the power for our train but the one diesel had failed in the yard and so the load was given to us.

The load was just under 1000 tons and consisted of all different kinds of wagons from hoppers to flat cars with bulldozers etc on them. Next to us was a long load of B bogies. I expect that would have been our load if the diesels had not failed.

While the vacuum ejector builds up the trains vacuum John and myself put our feet up and have 5 minutes rest, it's been a very long day so far and we are now about 3 hours behind time much of it due to us spending so long in the loco shed. About 20minutes later we are awoken by the sound of a shunter shouting "Drywer, Drywer, as julle reg is julle kan maar ry" (Driver, Driver, if youíre ready you can leave). On that note I immediately open the blower and put the stoker into action. Black smoke is pouring out of the chimney indicating the fire is going well. Before john opens the regulator I grab my video camera and run ahead of the train to get a false start out of the yard. As the engine passes I climb on boar and start getting the fire ready for the long climb ahead up Bhershoek bank.

As we turn onto the mainline John works the engine gently like any good steam driver would simply to give the fire and cylinders time to warm up. With steam right up at the red mark as we cross the Olifants River in the valley John opens her right up for the steep climb. Again it seems strange not hearing a beat from the exhaust. As we head up the bank 3511 is performing great and it is now video time for me. The wind in the valley had almost gone but as we get closer to the top of the bank at Bhershoek the wind is getting stronger but it certainly does not feel anything like it was on the way down.

We approach the summit with a full head of steam and doing over 40kph. I hold my camera out of the cab window simply to get the sound of the fan slowing as John shuts the regulator. It sounds just like a jet plane that has landed and is slowing down the engines. If one had to play that sound to anyone who is unfamiliar with the condensers they would not believe that it was a steam locomotive. As the train is loaded we pick up speed very quickly down the bank towards Houtkraal. With greens all the way we glide through the station at about 80kph. With such a free running train itís not even necessary to open the regulator through the dip that the station is situated in and its feet up time for us all the way to Potfontein. The signals at Potfontein are green and that means itís time to get ready for the short climb ahead. The steam is sitting nicely at 210psi but a quick peep into the fire reveals a rather dead fire. I open the blower immediately and start up the stoker. Within seconds smoke starts appearing from the chimney. As we race through the station John winds the reverser back and gently opens the regulator. I shut off the blower as the exhaust from the cylinders will now keep the fan turning. Another peep into the firebox reveals all is going great and the fire is white hot.

The line from Potfontein to Orange River has 3 rather short banks but all are hi speed and so the fireman has to keep a good eye on things otherwise he will be in sh'/t. The first bank is the shortest and 3511 flies up it on less than half regulator. Two km further and the hardest climb out of the 3 begins. Here john winds the reverser back and opens the regulator until the steam chest pressure gauge reads 150psi. I keep the stoker feeding as slow as possible and even with no 1 pump running full time the steam pressure is creeping up towards red mark. I put on no 2 pump hoping it will bring down the steam pressure slightly but no, even with the slow speed of the stoker the steam goes on rising. I then turn off the stoker and after a while the steam starts to drop slightly and I turn off no 1 pump. Turning the stoker off while the engine is working so hard can lead to trouble later. Holes can appear in ones fire causing sparks to fall into the ashpan and set the veld alight. The fire can also get rather too thin or even rather dead and then you really are in the sh'~t. Lucky for me the fire remains good and we reach the top of the bank with full steam and water in the boiler. Itís now along the level for about a km then downhill to Poupan where we charge the next bank to Rooidam summit.

Poupan is one of the fastest sections of the whole De Aar line and so long as the distant signal indicates a green aspect drivers would always take power while flying down towards the station and charge the short but steep bank just like we do on 3511. From then it's a easy trek to Orange River. Here once under the water column it takes me less than 5 min to clean the fire. With time on my side I decide to feed the pumps a bit of oil. As no special pump oil was available at Kimberley I simply pour some cylinder oil down the steam inlet pipe. This oil is rather thick for such machinery as turbines but any oil is better than none. With water full and fire burning white John gives a quick tug on the whistle and the road is cleared for us to leave the half way point. Ahead lies a long non stop climb of about 70km to Enslin summit. It is also a rather hi speed section so any loss of water in the boiler means it has gone and it is almost impossible to get it back into the boiler without using up steam pressure. Hopefully this wonít be the case today.

As we head up the bank towards Witput 3511 is going like a dream. I am now getting use to this wonderful machine and have its stoker down to a fine art and since she is steaming so well itís time to start seeing what all these other levers etc can do for performance. I decide rather than keep going back and forth to open and close the fresh water valve feeding water into the condensate tank I will just set it very slightly open. This should hopefully keep the condensate tank at a constant level. Next thing is the temperature of the water to the pumps. Remembering what happened before I don't want it too hot otherwise the pumps may trip. I increase the temp slightly. I know that by increasing the temp too far loads of steam and not much water will be fed into the pumps and this will cause them to spin too fast and less water will be fed into the boiler. What I really want to do now is get a good balance by using both pumps and the temp set as high as possible then that should require less coal to make steam. I play around with the whole set up and before I know it we have reached Enslin. It has been a wonderful trip so far. As we race down the bank towards Heuningnesskloof we are well over our allowed working time of 16hours. But when one is having fun who cares about time. We approach Heuningnesskloof and all signals are green but just as we race over the level crossing we see a minibus heading towards the station and we know what it is. It is another crew to takeover our train to Kimberley. As we fly through the station at over 100kph they wave to us thinking we would stop but nothing was going to stop us now, we were having too much fun. Just as we pass the advance starting signal it falls back to danger. We know the signalman tried to stop us but was not quick enough.

It is now a race against the minibus to Modder River. We keep the train flying along at over 100kph all the way down the bank opening the regulator at times as needed. As we approach Modder River the minibus is just about catching us on the road alongside the line. They are flashing the lights at us to tell us to stop at Modder River but with green signals showing John winds back the reverser and opens the regulator. We are now going faster than ever as we fly past our relief crew on the platform. Secretly I don't think they really wanted to takeover the train and just left us to get on with it otherwise the signals would have been set to danger.

As we race up the very steep section out or Modder River the boiler is getting rather full and steam is just about to lift the safety valves. In other words the boiler is about to burst. I stop the stoker and leave both pumps running but turn the condensate temp down as cold as possible. Within a few seconds the steam starts to drop and I restart the stoker. Things are just going great. With the stoker going again I keep a close watch on steam and water. I increase the condensate temp slightly and try to get a balance between stoker, water and steam and this is finally achieved as we race along overtaking the cars on the road alongside us.

The next section up to Spytfontein is one of the steepest banks on the whole line and most 25/25NCs require the cut-off to be lengthened half way up the bank and today is no different. As we round the first curve 3511 is still doing about 80kph but as the line gets steeper her speed decreases and ahead lies a rather sharp right hand curve on a very steep grade. John knows this curve will bring her speed down even further and rather than let the cut-off out on the curve and cause the engine to go into a violent spin he eases the regulator on the straight and lets the cut-off further out then re-opens the regulator. With the cut-off set higher, this means more steam is going through the cylinders and so the fan is turning even faster causing more pull on my fire. It also means that more water is being used. I increase the speed of the stoker very slightly but the steam pressure starts moving away from the red mark and with plenty of water in the boiler I simply decide to turn off no 1 pump. The steam starts to climb up again and so rather than turn on the 2nd pump I lower the temp of the condensate feed water to the pump that is running. With the speed way down one pump should manage to keep the boiler topped up with no problem. If due to the cooler feed water the steam should start to fall I will simply increase the speed of the stoker or if steam gets too high I can always put on the 2nd pump and so it goes on. Once up through Spytfontein it is a very fast race track to Kimberley and with the minibus driving alongside us on the main road we are soon hitting 100kph plus. We fly across the level crossing at Wimbledon and John shuts the regulator. We drift downhill and are signaled into the arrivals yard. With load uncoupled we slowly make our way back to the loco shed and park this wonderful unusual breed of engine under the coal stage. While I unload the kit John inspects the engine and books any repairs that are required.

As we walk into the sign on office there stands the crew that had been chasing us for the last 60km. "What kind of bloody speed were you doing with that machine" were the words from the driver. "We've been trying to catch you since Belmont".

And so ended our first trip on the Condenser. The trip down was destroyed by the rubbish coal supplied by SAR but that trip back was a totally new learning curve for myself. It was one of the best trips I ever had on steam. As for the engine I soon learnt to fire it well and worked out all its little tricks. It is a much more controllable machine than the normal steam locomotive in that one has more control over what temp your feed water can be set at. Together with that and the speed of the stoker one can have a grand time keeping the steam and water constant in the boiler."


Rob Dickinson

Email: webmaster@internationalsteam.co.uk