C2 Project News
A lengthy report from our busiest working party to date
An out-of-season weekend in late November in Porthmadog can be a very quiet time. This was definitely not the case on the weekend of our November working party though. All six C2 project members were present, along with six volunteers to assist us, making it our busiest ever working party! With two other working parties on the railway the same weekend, Boston Lodge works and the pubs in Porthmadog were buzzing with activity.
We had been expecting to have some helping hands, so in the weeks leading up to the working party we had carried out some preparatory work. Steel for suspension pillars and the heads which fit to them had been ordered. Vesconite (a material similar to PTFE) suspension pillar guide bushes had been ordered from South Africa, along with a rod of Vesconite for us to machine other bushes from. Felt seals for the axleboxes had also been ordered. All of these items arrived prior to the working party, along with the horn wedge faceplates and adjusting bolts which had been ordered previously from Sanderson Engineering. It was like Christmas a month early unpacking all our presents!
Andrew spent a few days at Boston Lodge in the week prior to the working party, and started machining the suspension pillars from stainless steel. He also moved the locomotive wheelsets (placed on the slate wagon last working party) into the carriage works to start warming up in readiness for painting. He even managed to get a first coat of paint onto the wheels on the Thursday.
Paul, Dave 1 and Chris 2 arrived at the works on Friday. First task was to move many of the suspension components, including the springs, into the carriage works to warm up.
Chris 2 is an experienced machinist, so we gave him the steel for the suspension pillar heads, along with a drawing of them, and he spent three days working on the 'new' (second-hand) Bridgeport mill, making the said items. The Bridgeport is a very fine machine, and happily chomps through steel like a hot knife through butter. Although the job was not completed at the end of the weekend, Chris 2 kindly offered to take the components home with him, so that he could finish them using Paul's home workshop (he lives very close to Paul). All being well, the suspension pillar heads should be finished by the next working party.
An unexpected bonus was that Colin also arrived on Friday. By a great stroke of luck, it turns out that he has a lot of experience of machining PTFE and stainless steel. So we gave him the task of machining and fitting Vesconite bushes, and making pins from the stainless steel we had bought. His first job was turning a special tool for pulling the suspension pillar guide bushes into the reamed holes in the frames. By mid afternoon on Friday they were all in, a complete contrast to the days of hard work pushing the old bushes out! With equal efficiency, he turned bushes for the front spring hanger brackets and the rear spring buckle eyes, and fitted them. By the end of the weekend, he had also turned the stainless steel pins for these locations too.
We had found it necessary to replace one of the horn wedges (position 4D), and so an oversized component had been fitted to the frames in that location. After a brief lesson on using the Bridgeport from Chris 2, Dave 1 used it to machine the wedge almost to size. It had to be machined skewed, since the horns on the frames at position 4D are distorted, and the skew compensates for this.
Most of the horn wedges had been ground to size, but there were two (3D and 4D) left to finish. These were fitted to the frames (after Dave 1 had finished milling 4D), measured, and then Paul carefully ground them to perfect size. It was an exercise that took several iterations, but by the end of Saturday the task was complete. This means that all sixteen of the fixed horn faceplates and horn wedges are now perfectly aligned.
On Sunday, Chris 1 and Dave 1 started to carry out the final fitting of the fixed horn faceplates and horn wedges to the frames. Chris 1 had applied wax spray to them the previous day, to protect them from corrosion. Using the correct fixings (previous trial fitting had used the old Chinese fixings) and the keys Andrew had machined previously, the plates were gradually fitted. Some minor adjustment to a few of the keys was found to be necessary, as this was the first time they had been fitted to the frames and the plates simultaneously. Similarly, a few of the screw heads had to be filed down to fit, as they are bigger than the old Chinese screws we took off (the Chinese had used undersize fixings which had come loose). By the end of the day, all the plates were fitted permanently. This, and the fitting of bushes to the frames, was the first step in the reassembly of the locomotive; quite a notable event.
With the horn wedges finished, Paul started to check the fit of the wedge faceplates. As intended, they are a very snug fit. The wedge adjuster bolts are similarly snug fitting vertically, but with a few millimetres of play laterally, just as we specified. Paul skimmed the front face of one wedge faceplate with the surface grinder, but the rest will have to wait until the next working party.
With a lot more people joining us on Saturday and Sunday, the rate of progress increased accordingly.
Andrew cut lengths of stainless steel bar, faced off the ends and rounded the corners, to make more of the suspension pillars. Andrew managed to get them all finished by the end of Monday.
Dave 2 was given some steel strip, and set about making replacement knife edges for locating the locomotive front springs onto the spring hangers. He has done a very neat job of shaping the components on a milling machine. Next task will be to radius some of the edges accurately. This will be done at the next working party, but with Paul's assistance, Dave 2 has worked out a method for carrying out the operation.
The weather was bright and sunny, but rather cold, so the warmth of the carriage shop meant it was a popular spot to work. Colin and Alasdair cleaned the locomotive springs and applied another coat of paint to them. Matt stripped off the old paint from the tender springs, cleaned them, and applied primer. Alasdair also applied a top coat of paint to many of the smaller suspension components.
The wheel front faces are one of the few parts of the locomotive which are not to be painted black, and so will be quite prominent when the locomotive is complete. We therefore want them to look good, and so painting of them needs to be done carefully. Alan and Andrew spent two days applying successive coats of red to the wheel centres and white to the tyres. With great care taken, the edges of each area of colour are razor sharp. Andrew stayed an extra day after the working party to get this task completed. The wheels do now look very smart!
We have had a number of Harbin works plates and forestry logo plates cast from aluminium. Some of these will be for fitting to the locomotive, while others will be for sale on our website merchandise page in due course. Chris 1 straightened out the works plates, drilled the fixing holes and countersunk them. After an unsuccessful first attempt, Alan eventually managed to find some suitable primer, and has applied it to the sunken areas of the works plates and forestry logo plates.
Much 'homework' has been going on recently. Paul has created a computer aided drawing of the tender, in order that we can check that all the equipment we need will fit. This is especially important at the interface with the cab, as we have reduced the width and height of the cab. In addition to the existing water hoses we are adding a steam pipe for the power brake on the tender, a vacuum pipe for the train brake, and electrical connections for lighting too.
One of the biggest challenges in reducing the cab dimensions is maintaining sight lines, especially when driving the locomotive tender first. We think we are arriving at a workable solution, but there is still a lot of detail to be finalised. We wanted to know if the existing cab door and side windows can be reused (we only have half as many as we need, so will need to make or buy some more), and to determine how much the front window frames will need to be narrowed to fit the new cab. Because the doors and windows are to a Chinese design, we don't have drawings of them in the original set of Russian drawings. These items were well buried in the shed, so Jon dug them out for Alasdair to take measurements and draw them up. Initial thoughts are that we should be able to reuse them, which will help to keep the C2 appearance. The new smaller cab to fit the FR loading gauge will look similar to the narrow cab fitted to our loco prior to its 1998 overhaul.
With most of our recent efforts going towards achieving a rolling chassis for the locomotive, the tender has been on the back burner for a while. But with so many hands available, we took the opportunity to get work underway on it again. Sam and Matt shunted the tender frames (on our flat wagon) from the C2 shed into the erecting shop, and turned them over so that they are now the correct way up again. Sam, Jon and Alasdair then set to with the oxy-acetylene torch and angle grinders to remove the final remains of the old tank floor. The remaining rusted-in bolts for the horns were also removed. With a little more cleaning up with angle grinders, the tender frames should soon be ready for the spine to be added and the front end rebuilt, in accordance with Paul's computer aided drawing work.
Boston Lodge works has recently invested in a weighing hook for use with an overhead crane. We therefore took the opportunity to use it to weigh the C2 locomotive frames. Accounting for the weight of the lifting straps, the frames weigh 1348 kg. This compares with a predicted weight of 1318 kg, calculated from the SolidWorks 3D model which Paul 2 has been creating. The centre of gravity position was within 60mm of the prediction. We consider the match to be very good, which gives us confidence in using other mass properties predicted by the SolidWorks model. We have since identified a few features in the SolidWorks model that did not exactly reflect the frames as weighed, and we think we can get the match even closer.
To finish the weekend, we asked Rob to take a photograph of the whole working party team. Stood out in sunshine, surrounded by glorious Snowdonia scenery, it's not difficult to see why we like working at Boston Lodge.