C2 Project News

September 2017

More Progress on the Tender and the Brakes

As is becoming customary, this month's C2 Working Party started on the Thursday. Andrew and Dave 1 spent the whole day checking the tender chassis frame assembly drawing which Andrew has produced against the actual tender chassis frame. Every dimension was carefully measured, and then ticked off when we were sure that the drawing reflected reality. This proved rather interesting....
Whilst the parts of the tender chassis frames which we have redesigned or replaced matched the drawing quite well (allowing for fabrication tolerances), some of the unmodified parts, the dimensions of which we had taken from the original Russian drawings, were found to be up to 20mm away from where we expected them to be. This is not a major problem, but it does mean that the front dragbox (which was positioned against one of the original bulkheads) is 15mm further back than we had planned. Worth knowing!

The accurate drawing of the tender chassis frames will now be imported into Paul's complete tender arrangement scheme, to make sure that all the other parts of the tender fit correctly onto it.
C2-800-795v2.jpg
These bonded rubber discs will be fitted to the shanks of the safety chain eyes at the front of the tender. The design of the loco-tender safety chains is an integral part of the loco rear bufferbeam and tender frame, so we have designed and purchased the components now.
Much to our delight, Dave 2 arrived a day earlier than we expected, and was soon at work fettling the steel plates which we intend to add to the rear headstock of the locomotive. These plates have to fit between existing plates on the locomotive chassis, fit around welds on the same, and have weld preps cut in readiness for attaching. With suitable breaks to give his hands a rest from the use of the angle grinder, Dave got the plates ready to be welded on.
Andrew was away on other business on Friday, but Paul joined the working party instead, having been driving trains the previous day. He set up the Bridgeport milling machine to make adjustments to the shape of the original brake block carriers we have, such that they will accept the standard brake blocks used on the Ffestiniog & Welsh Highland Railway's Funkey diesel locomotives.
We do not have sufficient original brake block carriers for the locomotive and tender, so we are making more. As noted in our previous working party report, the profile cut plates for the new brake block carriers had arrived, so Dave 2 used an angle grinder to remove the mill scale from the plates. He also used a linisher to neaten and debur the edges; we don't want anyone to encounter any sharp edges when changing brake blocks in the future.
Dave 1 used the Colchester lathe to drill and ream out a hole through the centre of the base of each of the tender equalising beam pivots. We will push new stainless steel pins into these holes, so they have to be an accurate diameter. He then used one of the Dean, Smith and Grace lathes with a four jaw chuck to turn a taper into the rear of the bore, such that we can run a bead of weld around it when the pivot is assembled.
It was Andrew's turn to drive trains on Saturday. While Paul had a well earned lie-in after a very enjoyable time in the pub the evening before, Daves 1 and 2 removed rust from the tender horn interfaces (where the horns bolt onto the frames) and took a set of measurements between them. This is the first stage in determining how to machine and grind the tender horns such that they are all perfectly aligned when fitted.
Paul arrived at lunch time, and continued working on the brake block carriers. Dave 1 used a wire wheel to clean the edges of some of the tender chassis platework in readiness of welding, while Dave 2 used a hand file to carefully restore the shape of the tender spring rocking washers which we have identified as reusable.
C2-800-798v2.jpg
Making a slot in the brake block carriers, on the Bridgeport milling machine. The new components were made from curved steel strip and profile-cut sideplates welded together by Andrew. The machining operations should ensure that all three types of carrier are interchangeable.
C2-800-797v2.jpg
The milled slot takes a tapered tang which retains the composite brake block on the carrier. Paul milled 15 of these; 10 new ones and the 5 surviving Chinese components. The Chinese ones are of two types with slightly different geometry and the milling operation revealed that one type is cast iron while the other type is cast steel.
Andrew was back in the works by 16:00, so he assisted Dave 1 in shunting the tender chassis frames (on our wagon) into 4-Road in the main erecting shop. He also welded up one of the new brake block carriers on the jig (made at the previous working party), ready for Paul to start machining in the morning.
Saturday evening was a little quieter than that of the previous day, so we all arrived in the works bright and early(ish) on Sunday. With four people available, mini production lines were set up, and the work stepped up a notch.
C2-800-803v2.jpg
Part of the new loco brake block carrier production line in the welding bay. - Andrew Nelms Sept 2017
Paul used the jig he had designed for assembling the new brake block carriers, and set up the next one ready for welding. Andrew then welded it together, before moving over to the tender chassis frames onto which Dave 1 had clamped the first plates to be welded. Whilst Andrew was welding them onto the tender chassis, Paul was milling the new brake block carrier. He then passed it to Dave 2 who ground off any weld spatter and sharp edges. Paul then set up another brake block carrier to be welded, and Andrew welded it while Dave 1 set up the next plate to be welded to the tender chassis. This continued all day. It was intense work, but by the end of it all 10 of the new brake block carriers were welded, milled and ready for painting, and all of the welding to be carried out while the tender chassis frames were upside down was complete.
Paul and Dave 2 had to go back to work on Monday, but Andrew and Dave 1 remained to continue work on the C2. First task was to turn the tender chassis frames over, to permit welding to be carried out on the upper surfaces. Trying to turn over an awkward shaped frame weighing (we estimate) 3/4 of a ton is not easy to do safely. After a bit of head scratching we asked Robco for some advice. He pointed us in the right direction, and with the use of the crane over 4-Road, a few chains and a pull lift, the tender chassis frames were quickly turned over in a very safe and controlled manner. Robco to the rescue again!

Now with access to the top surfaces of the tender chassis plates, Andrew and Dave 1 took turns to complete the welding of the plates added the previous day. The welding of a few other previously added plates was also completed where this had not been possible before because of poor access.
C2-800-792v2.jpg
After turning the tender frames over, we had better access to complete the welding of the new front-end frame components; here Andrew welds on the bottom flange. Although the exterior appearance of this part of the tender remains as original, we have redesigned the structure and drawgear so the internals are quite different. The old design had spaces which trapped coal dust and moisture, causing severe corrosion. Hopefully our new design will reduce that problem.
C2-800-793v2.jpg
Andrew welding the replacement parts of the tender frame, which is now the right way up. Behind the screen on the left is the first bogie carriage to run in the British Isles, dating back to 1871. Carriage 15's original wrought-iron frame is still in fine condition. Our steel tender frame is 117 years younger but led a hard life in China!
After four or five hours work, the bottom flange around the front of the tender chassis is now attached, the front dragbox is complete, and the nasty flame cut holes in the original bottom plates are all plugged with new material. This means that 95% of the welding on the tender chassis frames is now finished.

Making use of the afternoon sunshine, the wagon with the tender chassis frames on was wheeled out of the erecting shop. Andrew and Dave 1 then set to with angle grinders and flap wheels, to remove any weld spatter, and to grind back those welds which need to be flush. There is still some more grinding required, but the frames are beginning to look rather smart.

The final activity on Monday afternoon was to shunt the wagon and frames back into the C2 Shed.
C2-800-801v2.jpg
Tender frames now turned the correct way up. - Andrew Nelms Sept 2017
C2-800-802v2.jpg
Tender Frames outside Boston Lodge erecting shop. - Andrew Nelms Sept 2017
Both Andrew and Dave 1 dropped into the works briefly on Tuesday morning, before heading off to their respective homes. Dave 1 tidied the wagon, which had been used as a collecting point for all the tools we had used over the weekend. Andrew got out the white spirit and black paint, and gave the drawbars another coat. They are almost ready for fitting now.

Postscript:

Andrew and Jon were back in the works again at the start of October and moved the loco frames into the main erecting shop at Boston Lodge. This will make it easier to weld on the reinforcing strips for the rear bufferbeam brackets. It's the furthest that the frames have travelled on their own wheels, and all went well over the life-expired trackwork!
C2-800-800v2.jpg
Coupled to the trusty shunty 'Moel-y-Gest', our frames are parked in the main Boston Lodge yard for a photo, with the mountains of Snowdonia in the background. The top of Snowdon itself is lost in the clouds, directly above the trailing wheelset of the loco.
C2-800-799v2.jpg
The C2's frames in the Boston Lodge erecting shop for the first time on their own wheels. On the right is double Fairlie 'Merddin Emrys' built in this workshop in 1879. There are a few original parts left after more than a hundred years use! Since the Merddin, five more new steam locomotives have been built here, plus countless more heavy overhauls and rebuilds.
We don't expect to get much work done on the C2 over the Vintage Weekend Gala in early October, but we're eager to get on with it again at the scheduled working party towards the end of that month.
News Archive 
August Bank Holiday 2017