September 26th, 2019

Engineering News September 2019


Since the semi-assembled frames were delivered to Tyseley back in Mid April 2019, we’ve been patiently waiting for Tyseley to find room to start work on them. We’d got a slot booked for late 2018 for this but with timing slipping with the machinist we unfortunately missed the window. Having spoken to Alistair and Bob at Tyseley and the group building the new County 4-4-0 it was decided the best way to approach this was to get both kits of parts ready and build the frames up in tandem, this meant less time in Tyseleys workshop and, as both frames needed very similar treatment, it would reduce the final assembly cost for both locomotives.

The frames got a thick coat of grease on all the machined surfaces and along with all the additional castings and brackets are waiting for space to become available for the next stage in the assembly.

Machined motion bracket

Machined cylinder block.

As this is out of our control it was decided to plough on with the nextstages of the build. The two major expenses left on this project are the wheels and the boiler so getting things under way for these are paramount.

Seeing as we already have the pattern for the leading and trailing wheels the obvious next stage was a pattern for the drivers. I modified the CAD model to create the pattern model and sent if off for quotation.

Leading and trailing wheel pattern

Driving wheel CAD model (C) Elliot Powick CME

Premier patterns who did the original cylinder patterns were asked to quote for a traditional pattern (like the leading/trailing wheel) and a poly pattern to see which was the sensible option. Once the quote came back it was plainly obvious that at £XXXX the tradition route was the financially sensible option.

Next in the line is casting the wheels. Wheel casting is quite a specialist process, having the combination of large mass of the centre boss and the outer rim, care must be taken not to end up fracturing any of the smaller, quite fragile spokes (Tornado having to have several fractures post welded and quite an additional cost) during casting. Having done some work for the 4709 Night Owl project I approached their project leader, Paul Carpenter for advice as they’d had a successful set of wheels cast for their project. Having successfully cast 4709’s wheels I approached Micron in Dudley (also handy due to the proximity of Premier) to quote for our 4 driving wheels and 4 leading/trailing wheels and they duly came back with a cast price of £7,480. The order for the pattern and 4 wheels will be placed in the coming weeks and put in a safe place to naturally stress relieve until they’re ready for they’re ready for machining.

Wheel casting.

The tyres and axles present a different set of problems. The axles really need to be forgings and the crank axle is very specialist indeed. A company in Sheffield called Railway Wheelset And Brake are the main importers of railway tyres from South Africa (it’s the place all preserved railways go) have been tasked in quoting for tyres for all 8 wheels, they can also do axle forgings so a quotation is expected for the leading and trailing axles and the trailing driving axle very soon. The crank axle is slightly more complex and might need redesigning to suit an alternative manufacturing process if RWB’s company in SA deem it too large for their forge.


Copy of original forged crank axle.

The Severn Valley Railway was approached late last year with a view of quoting for the boiler for the Loco. Because the boiler is a relatively simple steel construction with a copper firebox the basic quotation came back at around £200-225,000, seeing as we weren’t ready for ordering and with the price of copper fluctuating this was just a guide price but one they were confident on as they are currently making a batch of very similar boilers for the IofM locomotives they were very confident on the pricing structure at that time. The other problem was also that their order books were full for possibly up to 4 years so an alternative was required, Step forward Heritage Boiler Steam Services. Andy and Robert are currently in the process of finishing the boiler off for The Unknown Warrior and were free at the latter end of 2020 to consider taking on the project but to expedite things I’ve already starting modelling the boiler (old drawings can be a tad difficult to read at times) and this also means I can start doing the flange blocks as required. These are needed whoever does the build and keeping them in house I can reduce the overall cost of boiler production and assisting the boilersmiths in completing the job quicker.

Elliot Powick CME, The Holden F5 Steam Locomotive Trust.

Boiler assembly (C) Elliot Powick


Front tubeplate former. (C) Elliot Powick CME


Formed plate (C) Elliot Powick CME