Engineering Report - June 2015

Locomotive Frame Assembly

Work continues on a number of fronts on the construction of The Unknown Warrior.

The major work at present is the permanent fitting of the cylinders to the locomotive frame assembly.

The sixty eight special fitted bolts have been delivered to Llangollen and work is under way. There are 5 different lengths of shoulder, depending on which components the bolts are holding. There are different combinations of cylinders, stretchers and bogie mounting to consider. The shoulder on the bolts as supplied are slightly over size to allow them to be turned to the exact size required on assembly.

One of the Fitted Bolts as supplied – Photo-Jordan Leeds

Each hole in drilled and then reamed to the desired size, the hole is them measured and the bolt is taken into the machine shop, where the shoulder is turned to 2 to 3 thousands of an inch (0.002” - 0.003”) larger than the hole. The bolt is then driven into the hole and fastened with a washer and nut. Each bolt costs £55 each and when you add the costs of the time taken to machine and fit plus the washer and bolt, the total cost to fit just one bolt is approaching £100. That’s £6800 just to bolt the cylinders to the frames.

If anyone wishes to sponsor the fitting of one (or more) of these bolts at £100 each, please contact the project office or you can find details of how to donate on the sponsorship page.

The four leading Sandboxes are under construction and will be fitted on arrival at Llangollen.

Brake System and Lubrication System

The locomotive Brake Cylinder from 8F 48518 is under refurbishment by Harco Engineering. The Tender Brake cylinder will join it soon. Martyn Hughes from Harco Engineering has offered to refurbish both these brake cylinders at no cost to the project for which we are extremely grateful.

Work continues on the design of the lubrication system.

Unfortunately, the offer from a member to work on the locomotive for a few weeks this summer has fallen through. We are hoping that it may be possible to re-schedule this for sometime later in the year, to make a start on the installation of all the copper pipe runs. If anyone else would like to help on this work, even for a few days please contact the project office. We will then be able to tie up the details and make the greatest benefit for the locomotive. Your help will be greatly appreciated.

The Braking system fitted to the locomotive will be similar to that carried by the Jubilee class locomotives. The reason behind this is that there are no surviving detail drawings of the original crossbeams and pull rods, where as there are several surviving Jubilee class locomotives whose details we can copy. Also we are following up on the possible availability of some spare crossbeams and pull rod parts from a Stanier 8F class2-8-0 which used the same parts. Acquisition of these will be a great saving on time and cost over making new, if their condition is good enough to use.

CAD image of the locomotive brake gear.

Pistons, Valves and Motion

At Llangollen, following the fitting of the cylinders, work will continue fitting the motion parts. These include the Motion Brackets, Rear Cylinder Covers, Slide Bars and Motion Girders.

Cylinder & Valve Covers at Llangollen – Photo- Gavin Shell

Manufacture of the Coupling Rod Bushes and Brasses continues at Llangollen Railway Engineering.

The refurbishment of the legacy motion parts is continuing by the volunteer gang at Llangollen. Many hours have been spent on mainly hand work to clean off the years of pitting and corrosion. The new Connection Rod is also receiving some attention to polish out the machining marks. Once again if anyone is interested in getting hands on with the Unknown Warrior, if only for a few days, please contact the office.


Assembly of the bogie continues apace at Tyseley Locomotives Works. The Bogie Centre casting returned from the remedial machining and has been temporarily mounted into the frame assembly. The Horn Guides have also had the final machining completed and are now ready for mounting on the frames. The fitted bolts for this have been manufactured.

Machining of the Axleboxes is under way and manufacture of the pins and fixings is complete.

Bogie Frame under assembly at Tyseley Locomotive Works

Axlebox machining underway at Tyseley

Photos – Kevin West

Machining of the Axle and Wheel Centres for the new Bogie Wheelset has been completed at Harco Engineering and the parts were delivered to South Devon Railway Engineering for assembly on 29th May.

Axle for the new Bogie Wheelset at Harco Engineering following machining.

Photo – Kevin West

Bogie Wheel being machined at Harco Engineering.

Photo – Harco Engineering

Bogie bolsters after machining at Harco Engineering.

Photo – Kevin West


The tyres are on order and should be delivered in early September. They then need machining, fitting to the wheelset and finally the profile can be turned. This is planned for completion by the beginning of October.


Work continues on the forming blocks for the outer firebox Steel Flanged plates at Tyseley Locomotive Works.

At LNWR Crewe, the Inner Firebox components are now in the new works at Crewe South, ready for assembly to start, along with the Barrel Rings rolled at Deepdale and the Foundation Ring components. An amount of machining is required on the corners before the sides can be welded on to form the complete part.

The steel Outer Firebox Wrapper sheet order has been deferred until after the steel wrapper sheets have been formed. These will then be measured and the wrapper sheets formed to fit. It is easier to do this than try and adjust either the Wrapper or flanged plates is there is a mismatch.

A meeting has been held with the LNWR Heritage engineers to plan the progress of the boiler build. Delivery has been agreed for the end of 2016 to allow time to fit to the locomotive frames ahead of a first steaming in the second half of 2017.


Work on the refurbishment on the Tender Frames continues at Rowlescourt Engineering. The new Rear Dragbox is ready to be fitted into the refurbished Frames.

Work on the Front Dragbox Assembly and the remaining parts required for the Frame refurbishment continues.

The design for the new tender tank has been progressing when time allows.


Future work planning

Planning the work schedule to complete the locomotive build is a major part of the project at present. Throughout the build we are looking to use the best engineers and centres for each stage. This autumn will see significant work completed on the locomotive, which due to the logistics of moving staff and equiptment, is not desirable to undertake at Llangollen. We have also received an invitation for The Unknown Warrior to attend the Barrow Hill 65 commemoration event at the end of September. So we have formulated a plan.


The Unknown Warrior will leave Llangollen in late September and move to Barrow Hill for display on 25th – 27th September at the Barrow Hill 65 event. This is a major gathering of LMS motive power, with representatives of almost all former LMS classes still in existence in attendance. Although the locomotive has been displayed at The Warley model railway show in 2013 and The Great Dorset Steam Fair last year, this will be the first railway enthusiast event The Unknown Warrior will have attended.


We are very grateful to Allelys Heavy Haulage, who have kindly sponsored the locomotive movement costs from Llangollen to Barrow Hill.



The Unknown Warrior being moved from Tyseley to Llangollen by Alleleys July 2014


Photo – Kevin West


The following week The Unknown Warrior will move to Tyseley Locomotive Works to have the Cylinder and Valve Liners fitted.


The Bogie which is being assembled at Tyseley will also be fitted following its completion, before the locomotive returns to Llangollen in early November. The Unknown Warrior will be on display at the Tyseley Locomotive Works Open Day at the end of October.

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