C2 Project News

February 2023

A busy month, with lots of progress

We had several working parties throughout February, with different groups working on various aspects of the project. Consequently there's quite a lot to report this month.
First up, in the week following our January working party, our friends Rob and Norman built the wooden cab mockup for us. We had provided drawings and paid for the materials but they kindly volunteered to do all the hard work. It was built up in the carriage works and then partially dismantled into a flat-pack ready for assembly onto the loco.
The wooden cab mock-up assembled on the ground, in the carriage works. Front 3/4 view.
The wooden cab mock-up assembled on the ground, in the carriage works. Rear 3/4 view.
The wooden cab mock-up assembled on the ground, in the carriage works. Side view.
The cab mockup reduced to a flat-pack, ready for assembly onto the loco. Materials were also provided for the roof, to be fitted after final assembly.
Then in mid-February, Dave 2 and Andrew finished off the work on the steel frame that supports the cab, with more cleaning-up of the fabrication and several coats of paint all over. This made the cab floor frame ready for fitting to the loco frame. They also moved the wooden flat-pack into the C2 shed ready for assembly.

Andrew then jetted off to California so he could miss all the excitement of the cab assembly.
Andrew drives a train on the Norgrove Railway in California. This is a private agricultural railway owned by a former FR driver. Photograph: Ben Abbott
The end of February working party saw some very visible progress being made on the C2, as well as significant progress being made on less visible but important parts. As usual, the working party started with Paul and Dave 1 having a planning session on Friday morning. Shortly afterwards, another Dave (we'll call him Dave 4 for now) and Will arrived in the C2 Shed and they asked if we might have any jobs for them.
The cylinder studs which we had ordered had arrived, so Dave 4 and Will fitted those required to hold the rear cylinder covers in place. There are 12 studs per cylinder cover, and each requires quite a lot of torque to fit it, so it took Dave and Will several hours to get all the studs in. After a final inspection of the piston rod gland packing boxes by Paul and Dave 1, it was then time to fit the cylinder rear covers. Since we do not intend to take them off again, the nuts were fully tightened on the studs; another task requiring some hard work.

While the cylinder rear covers were being fitted, Paul took the cab floor shims made at the January working party, into the machine shop. Using some very fine shims, he mounted each pair of cab floor shims on the Churchill surface grinder and used it to grind a slight taper on them. Since the works' staff were in on Friday, Paul was able to demonstrate his proficiency on the surface grinder to Dewi, and this now officially recorded under the FR's improved competence management system. Paul then stamped each cab floor shim with markings indicating which position it was intended for, and which way it was tapered. Once finished, Dave 1 applied primer to the cab floor shims.
Dave 4 tightens the cylinder cover nuts on the newly-installed studs.
With the cylinder rear covers in place, Paul and Dave 1 fitted the slidebars. The measurements taken at the January working party allowed approximately the correct amount of packing to be fitted each side, which made measurement more accurate. The cylinder centreline measuring equipment was then fitted, and our newly acquired laser was attached. Rotating the rods on the cylinder centreline, to which the laser was attached, allowed Paul to plot a series of points in a circle on pre-prepared "target plates" which were fitted at different points along each slidebar. The target plates were then scanned and imported into graphics software on Paul's laptop computer. This allowed the centre of each circle to be found quite accurately. We had noted datums on the target plates, so the offsets of the circle centre (the cylinder centreline) relative to the datums could be found.
Laser target clamped to the slidebar, set at right angles and with the outer faces flush.
Using the laser to mark a circle on the target plate. The laser itself was attached to a rod accurately centred in the cylinder bore, which was rotated to produce the circle.
More work on the computer, this time using a spreadsheet, allowed Paul to determine exactly how much packing will be required to ensure that the slidebars are exactly parallel with the cylinder centrelines. To make things easier, we also want to mount the slidebars at the same height each side, which will be possible by careful adjustment of the thickness of the front and rear slidebar packing pieces.
Overview of the laser alignment.
Determining the slidebar offsets from the laser target plates.
Bobby and Helen joined us on Saturday, and were set on the task of fitting the cab floor. Firstly, the cab floor support angles had to be fitted to the rear bufferbeam and the centre cab support brackets. It is not intended that these angles will be removed again, so they were fitted with new bolts, nuts and spring washers. It was then time to place all of the cab floor shims in place (checking the stamped markings carefully) and them lift the cab floor structure into place. We expect to have to remove the cab floor structure to permit more work to be carried out on it when the final cab is assembled, so on this occasion temporary fittings were used to bolt it into place.
The 'Wooden Waggon Federation' volunteer group formed a couple of years back and has been overhauling some of the heritage coal waggons. Sometimes the WWF and C2 working parties have happened to coincide, but for 2023 we have made a conscious effort to synchronise them where possible. We use different parts of the Boston Lodge workshops but it's good to have some cameraderie in the brew room and in the evenings. This time, both groups were able to help each other in practical matters too. Whilst car-sharing on the journey to Wales, Julian had explained the difficulty they were having extracting a corroded steel tie-bar from the underframe of coal waggon no. 19, which was proving very reluctant to be removed. Paul proposed a method of drawing it out, which would require a thick metal plate with a hole in it, a simple job for us but none of the WWF people were familiar with the metalworking tools. So Helen was seconded to the Wooden Waggon Federation for a couple of hours, to make the plate for them. Initially the plate was used as a jacking plate, with nuts and washers being used to jack the tie-bar out of the underframe. Once the tie-bar was sufficiently withdrawn, hammers were used the hit the plate to further encourage the tie-bar out. Shouts of jubilation could be heard across the Boston Lodge site when the tie-bar was finally extricated!
Back in the C2 Shed, Bobby was assisted by Paul and Dave 1 in lifting the wooden cab front into place. Assisted by Dave 2, the cab sides were then positioned and screwed to the cab front, followed finally by the cab rear. A few minor adjustments were needed to get the cab mock-up to fit precisely; clearing a few bolt heads and fitting up against the intermediate cab support brackets. It was time for us to call on the WWF expertise, and Julian made some of the adjustments needed to the cab. These were completed by Dave 1 using a jigsaw lent to us by the Wooden Waggon Federation.
The wooden cab sides, front and rear, form a rather flexible (i.e. floppy) structure on their own, so we have some sheets of thin plywood to make a cab roof. Bobby and Helen screwed wooden blocks to the cab front and rear sheets, as well as to the intermediate roof former. These will take the screws which hold the roof sheeting in place. However, before the roof sheeting is fitted (and the cab structure becomes more rigid), we want to make sure it is correctly aligned. At present the cab rear is sitting perfectly on the cab floor frame, but the cab front looks to be skewed relative to the boiler. Looking along the plane of the cab sides suggests that the structure is a little twisted. We need to take some more measurements before proceeding further, to understand where the discrepancy lies and how to correct it. The cab mock-up being made of wood should make this an easy process.
Dave 2 helps to assemble the wooden cab mock-up onto the loco.
Julian (from the WWF) carries out some minor surgery on the wooden cab, while Bobby holds it in place.
The cab sides and ends assembled onto the loco. This gives a good idea of the revised proportions of the cab to suit the FR loading gauge: we have attempted to retain the original character in something slightly smaller than our loco's original cab.
Zoe joined us on Sunday, and offered to make the slidebar packers for us. Although Zoe has been a regular at Boston Lodge for quite a few years now as a member of the footplate crew, this was her fist time working in the workshops. It took her a while to find everything, but by the end of the day good progress was being made on the front slidebar packers. She very kindly offered to take them home with her to finish them there. We hope that Zoe will become a regular helper at C2 working parties as she is a skilled machinist; something that we really need at this stage in the project.
A 1980s Harbin-built C2 numbered 01, with a narrow cab, photographed in March 1989. A second very similar loco is visible on the far right, and an older Shijiazhuang-built 28t loco on the left. (Photo: © Nick Lera)
Erle arrived Saturday morning with a completed Turbine having finished off riveting the 110 pins of the Turbine blades to the main Turbine body at home. The Turbine was then mounted to the Generator shaft using the Governor Body and Taper seat to lock it in place. Care was needed at this point to ensure the Turbine was correctly positioned as it will be rotating at 3500 RPM next to the Steam nozzle on the Turbine Cover which has a gap of 0.5 mm. The Turbine Cover was then fitted.
The Generator at present is having its Regulator and Governor worked on and would not be available, however it was decided compressed air could be piped in directly to the Steam Nozzle to test the Turbine and the Generating side. To this end Erle set out to make an adapter plate to secure to the Turbine Cover and scoured the stores to find suitable compressed air fittings to attach to it. By the end of the day this was complete. At this point a discussion was had about the possibility of setting up a light along with a Voltmeter to measure the Generator output of 50 Volts. After a search no lighting could be found which would handle this voltage. A discussion with Dave 2 came up with an idea of linking 4 off 12v car light bulbs as a possible solution but these were not available so the day finished.
Unbeknown to everyone else Dave 2 that evening decided to put together a lighting rig from some 12V bulbs he had at home, and soldered and clipped them together along with a Test meter. He then duly delivered these to Dave 1 that evening.
The first glimmer of light from the turbogenerator. After all Erle's careful work on the mechanical side, and the outsourced electrical attention, it does actually work!
Erle and Dave gradually increase the air supply to the turbogenerator, monitoring the voltage and rpm while the lamps get brighter.
The next morning Dave 1 delivered these to the Generator. Erle then set to fitting the compressed air adapter plate. After some discussion with Paul, the nearest compressed air connection point was found in the Engine shed and after a bit of hose gathering, a series of compressed air lines were run over to the Generator. Paul then switched the compressor on, and after some checks we were ready to go.

Erle then carefully opened the compressed air valve and the Generator started to turn and the voltmeter started to register a voltage. Dave 1 at the same time started to use an Optical Tachometer to measure speed. After a few minutes of listening, the speed was increased and slowly the Generator was brought up to its operating voltage and the light bulbs then started to glow. This was repeated a few times with Dave 1 also having a go. It was a successful first test with the Generator running smoothly, being able to deliver its operating voltage and no sign of bearings heating up or undue vibration. The Generator gives a distinctive sound of a motor running at high speed.
At 3000rpm, the turbogenerator was producing the rated 50V. This was with a relatively small electrical load and powered by air at around 100psi. We will put together a higher-rated load bank next time.
Our next regular working party is at the end of March, with a smaller attendance as several of us are unavailable. However, we anticipate more progress over Easter when several of us will be at Boston Lodge for a longer period.
News Archive 
January 2023