May 2024

There was no working party at the end of April, since the May Day bank holiday fell on the first weekend of May. As there was another bank holiday at the end of May, we have had two working parties this month. Lots has been achieved as usual but there is still so much more to do.

Due to the bank holidays, this meant that we could spend three days working on the C2 instead of just two. Andrew had also managed to spend a day or two working on the C2 a fortnight earlier in April, which enabled him to advance the job he has been working on.

As explained previously, Andrew has been trying to true up the expansion link spigots on the cover plates. Correcting the first pair of cover plates went fairly well, as the spigots were not too badly aligned. When we say "not too badly", we actually mean "pretty awfully", but they weren't as bad as the second pair! The second pair of plates not only have very badly aligned spigots, but the lateral bearing faces are also badly worn. Andrew and Dave 1 considered scrapping them and starting again from scratch, but eventually decided to persevere with them as there would be just as much work required to make a new set.

Andrew skimmed the spigots of the second pair of expansion link cover plates, using one of the 17" DSG lathes with the bed extension removed. He also welded up the original centre holes in the spigots and re-machined them, this time in the centre of the spigots!

Dave 1 took careful measurements of the motion bracket holes into which the expansion link bearings will fit. He had machined these out several years ago, to correct misalignment of them. We propose using Vesconite bushes in these holes, with stainless steel sleeves on the expansion link spigots. Since Vesconite bushes need to be thinner than equivalent steel bushes, the outside diameter of the sleeves will need to be bigger to compensate. This is fortunate, as it means that the new sleeves will have a significantly increased wall thickness, allowing the sleeves to be machined off-centre when correcting misalignment of the spigots.

Dave 1 also undertook some turning work, making new stainless steel pins for the joints between the return rods and the expansion links. The pins still require holes for keys to be machined, and a groove beneath the head, but are now well advanced.

Also bolted to the expansion link covers are the lubricator drive brackets. Dave 3 kindly offered to clean the brackets up, removing any damage to the original bracket (the other one is new). He then set about reaming the holes in the brackets at the same centres as those on the expansion link cover plates by using the cover plates as templates. One hole in one of the brackets will require a little more work, but all the others are now finished.

Sam made a welcome return to our working parties and was tasked with checking that all the necessary control equipment will fit in the cab. Sounds simple, but it is a significant job. Firstly, all the controls had to be found; fortunately not too difficult since we try to keep the C2 shed tidy and we generally know where everything lives. Some of the parts, such as the reverser and regulator, then had to be temporarily reassembled.

With the original boiler mounted on the frames, it was fairly straightforward to refit most of the controls to their original brackets. This immediately showed a problem. We have lowered the cab, so the injector delivery pipes now pass through the middle of the front windows. That's not going to work! The fixing holes on the injectors are 4" apart, one above the other. Dave 1 realised that by hanging each injector on only the lower fixing point of the bracket, they could be dropped by 4", which solves the problem. However, it will be very difficult to design a new bracket to hold the injector on the driver's side, since the reverser is directly below the bracket. That's going to require some thought.

The reverser which was fitted to the locomotive when we bought it had two sets of mounting holes, so it could be mounted forward into the cab by about 40mm. Doing so seemed to create a bit more space on the driver's side, but Andrew observed that the reverser handle was now very close to his knees when sitting on the driver's seat (mocked up by a stool placed in the cab). This confirms that we want the reverser to be mounted as the chinese had modified the design and not in its original design position as shown by the original KP-4 design drawings.

There is further equipment in the cab below the injector and reverser on the driver's side. To date, we have only fitted the main cab floor, but we now wanted to fit a floor to the raised front cab floor area beside the firebox. Sam found some plywood and cut it to fit. James cut some blocks of wood, screwed them to the new floor piece, then screwed it into place in the cab. This provided us with a surface onto which we could place the additional equipment. Sam found a length of plastic foam pipe insulation which, when cut in half, was an ideal representation of the water inlet and overflow pipes from the injector.

One of the modifications which the Chinese had carried out to the original KP-4 design was to move the draincock operating rod from the fireman's side to the driver's side, and to make it operated by a foot pedal. We have lowered the main cab floor by 100mm, which makes the front cab floor appear higher. Sitting in the driver's position, the foot pedal for operating the draincocks is now uncomfortably high, so it looks like we may have to sacrifice the foot pedal and revert to the hand operated push/pull lever of the original KP-4 design. This would also have the advantage of freeing up some much needed space beside the firebox on the driver's side.

Sam also found and fitted one of the blow-down valves. These are mounted outside the cab, just in front of it, but are operated by levers inside the cab, on the raised front floor areas. The narrow cab means that the operating rods will be close to the side walls of the cab, but they just fit. Access to the operating levers will require reaching past many other pieces of equipment, but we do not consider that a serious problem as the blow-down valves should not be operated very often and we certainly don't want them to be operated accidentally.

As if the reduction in cab height and width do not cause us enough of a headache when fitting all the controls in, we need to fit some extra controls. The new proportional steam brake valve is a beautiful piece of equipment, but it is also rather large. We could find nowhere that the valve and operating handle could be fitted and remain within reach of the driver. The same (or a very similar) design of proportional steam brake valve is fitted to Taliesin, which is currently stripped down for overhaul in the erecting shop. An inspection of Taliesin's cab shows that it is possible to separate the valve and operating handle, such that the valve itself can be mounted at a lower height. If we do the same, we should be able to mount the operating lever against the cab side with the valve below, near the floor. As such, it might just fit.

At times, installing the equipment in the cab felt like we were taking one step forwards and two steps back, as each problem became apparent. But that was the purpose of the exercise; to find the problems now when they are easier to solve. We have identified several issues, but we have some ideas as to how we might resolve them. And all before any metal has been cut!

At the second working party of the month, Erle was able to join us and spent the weekend in the machine shop continuing to machine the new reverser base plate. This is continuation of what is shown in the previous news update.

Dave 1 was unable to join us but Dave 2 was able to join Andrew and Erle for what was a quiet but productive working party. Andrew and Dave 2 spent the weekend completing and fettling the drain cock linkages. This was a rather fiddly job which required careful setting up and measuring so that the one operating lever opens and closes all 4 drain valves exactly simultaneously. By 5:30pm of the last day of the working party, a trial fit and operation of the valves was completed successfully.

At the moment, operation is only from the weighshaft. The reach rod connection to the cab is the next job on the list and requires careful measuring as a bend is required in the rod. Also a new handle needs making as the foot pedal control cannot be fitted in the new cab.

There is still much to do and were still hoping for some exciting news on the new boiler design soon. As soon as we ehave it, we'll let you know here!