January 2025

The January C2 Project working party took place over the weekend of 18th/19th, and was extended through until the Monday. Considering it was a mid-January weekend, Boston Lodge was amazingly busy. As well as the C2 Project working party, there were metal waggon and wooden waggon working parties, the electrical team were upgrading the electrics in the blacksmiths' shop, the machine shop was full of trainee machinists funded by the Heritage Lottery Fund, and several of the regular works staff were in working on their own projects. The new 'Den' (mess room) may be bigger than the previous one, but it was still at capacity at lunch times.

Having removed the safety valves at the last working party, Jon started to dismantle them. Removing the locking nut on top allows the pressure adjuster to be unwound. Most of the parts are accessed from below though, and the joints between the steel bases and the bronze bodies remain stubbornly seized. Jon has therefore left them soaking in penetrating oil, and will apply some heat at a later date.

Something else that will be required before the new boiler can be tested is the regulator valve. Dave 1 located it, along with the dome-side gland, the control shaft and associated parts. First task was to use a wire wheel to remove any corrosion and lime scale from the parts, with Dave and Jon working on this.

Dave dismantled the valve spindle so that it could be withdrawn and assessed. It is generally in a fair condition, but the screw thread at the end is very badly wasted. We will have to carry out some repairs on that part.

Dave had a discussion with Adrian about regulator valves, as Adrian has recently had the NG15 regulator overhauled. An inspection of the parts and drawings shows that the C2 regulator valve is a rather simpler design than that of the NG15, which will hopefully make it easier to overhaul.

After cleaning, Dave primed the parts which are external to the boiler. Parts which are internal have been coated in spray-on wax, as we don't want paint flaking off inside the new boiler.

The regulator gland is a Chinese adaption of the original design. Instead of rope packing, the Chinese have used PTFE. If it works, then why not? There is also a bronze bush inside the gland which Dave measured and found to be badly worn. He therefore turned up a drift of the correct diameter and used it to drive out the old bush. This showed it to be a very much simpler shape than the original design. The simpler shape probably works, but also likely contributed to the wear. Current thoughts are to make a new bush to something more like the original design.

The new boiler will also require water gauges and associated parts (isolating and drain cocks) before it can be tested. The original boiler was fitted with a Klinger type water gauge. However, after taking advice from several of the works staff, we have decided to adopt a more conventional design which is common with that used on all other Ffestiniog and Welsh Highland Railway steam locomotives.

Jon Whalley advised us of the suppliers that the FfWHR use when they purchase water gauge glasses and associated parts. Andrew and Dave took a look at a number of FfWHR locomotives to understand the arrangements which are normally employed. This has given us a very good idea of what parts will be required.

The Klinger design of water gauge comprises a number of individual parts, and is therefore relatively tall. The conventional design uses a single glass tube, and so the top and bottom fittings are normally placed closer together. The C2 boiler design has widely spaced top and bottom fittings to suit the Klinger design, which would result in an undesirably long glass tube. Andrew and Dave spent some time looking at the existing boiler, to try and understand if we can adjust the positions of the top and bottom fittings to shorten the glass tube. Whilst there is nothing on the outside of the boiler to prevent this, there are structural parts inside which have to be avoided. This will take a bit more thought to resolve.

Andrew spent a day in the C2 shed the previous weekend, cleaning up one of the crossheads. He has also now cleaned up the second one.

The crossheads fit around the slidebars, with a top casting (which also forms the oil reservoir) fitted between upwards extensions of the sides of the lower part. It all needs to be very rigidly held together, employing fitted bolts to do so. Of course, the existing holes are all worn and oversize. Andrew therefore located a set of reamers which he could use to enlarge the holes (three per crosshead) to restore them to a known and consistent diameter.

Using a drill shank, Andrew carefully aligned the central holes in the two parts of one of the crossheads. The parts were then bolts tightly, and the assembly mounted on a milling machine. As the second reamer was driven through, the remains of a sleeve fell out the bottom of the hole. Clearly that crosshead have been repaired previously! It was then a case of finding larger reamers to remove as many of the witness marks as possible, to leave the hole in a good condition.

To keep the finished hole perfectly aligned, Andrew turned up a dowel to put into the hole. While he was at it, he turned up a second dowel, as that was likely to be useful too.

With the dowel inserted, one of the remaining bolts could be removed and that hole reamed. Finally, with the two machined holes dowelled, the third bolt could be removed and that hole similarly treated. Then on to the second crosshead to repeat the whole process! After a couple of days work, Andrew has restored the holes in the crossheads ready for new fitted bolts.

With so many people present over the weekend, a great deal of socialising took place. The Thai Harbwr (our favourite eating establishment in Porthmadog) did us proud, and we also enjoyed food and drinks in The Australia pub. The Pencei pub accommodated us on several evenings, with the 'railway crowd' filling the upstairs pool room on Saturday evening. Coupled with satisfying progress being made on the C2, a thoroughly enjoyable weekend was had.