Engineering Update - May 2015

Locomotive Frame Assembly

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

The cylinders are back at Llangollen following specialist treatment to cure the minor leakage found on hydraulic testing and are now in the process of being permently fitted to the locomotive frames. The 68 special fitted bolts required for this are in manufacture and will be at Llangollen by the end of next week. There are a number of bolt lengths required as various areas share the same bolts to hold a combination of single cylinder, both cylinders or a cylinder and a Frame Stretcher. The bolts are all manufactured with the shoulder diameter larger that required. The holes are drilled through all parts, then reamed and measured to establish the exact size. The shoulder of the bolt for that hole is then machined in a lathe to be slightly larger by a couple of thousands of an inch (0.002”). The bolt is driven into the hole with the help of a large hammer and held by a nut. This method is used to ensure the cylinders do not move on the frames. Over time if movement is found, it can be corrected by driving out the bolt, reaming the hole slightly larger and fitting a new bolt. The same method has been used on the Axlebox Horn Guides.

The LH cylinder mouning at Llangollen shed. 2nd June 2015. Work is in progress drilling and reaming the fixing holes. This view is one not normally seen as it is taken through the RH Frame where the right Cylinder is normally found. The unpainted area at top left is where the Smokebox mounting stretcher is fitted. Above and behind the cylinder exhaust pipes is where the Smokebox side base pieces fit and to the right the inside cylinder. At the bottom is the fixing holes for the Bogie Centre Pin Casting.

Left hand Cylinder being fitted to the locomotive frames.

Photos – Kevin West

Other work continues on the Frame Assembly as time and work force availability permits. Once again this month Arwell and Chris have been called on to work on the return to traffic of Llangollen Railway based GWR Pannier No 6430, so progress has been slower than expected. Discussions with Llangollen Railway have continued to see if we can obtain grant funding for extra staff for the future.

The volunteer gang continues work on the locomotive frames and Driving Wheels. Work has started on refurbishment of the legacy motion parts acquired from Jubilee class locomotives a couple of years ago.

David Hughes who organizes our volunteer working parties stands with the almost complete locomotive Driving Wheels.

Photo – Gavin Shell


The four leading Sandboxes have been ordered.

Work is continuing on machining various casting related to the valve gear and reversing gear. Design work is continuing on the remaining parts required. A number of parts have been sent out for quotation for patterns and casting.  

David Hughes points out something to Chief Engineer Kevin West. The boiler tubes for 7822 Foxcote Manor come in handy as a makeshift office desk for the design computer and some original drawings. – Llangollen Works – 2nd June 2015

Photo – Gavin Shell

Brake System and Lubrication System

The locomotive Brake Cylinder from 8F 48518 was moved to Harco Engineering last month. This has now been stripped and shot blasted ready for refurbishment to start. The Tender Brake cylinder is presently at Rowlescourt Engineering with the tender chassis, but is due to be moved to Harco for refurbishment. 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..

Tender Brake Cylinder

Photo – Kevin West

Work is also underway on the design of the lubrication system. As mentioned in last months report, we have the offer of a volunteer who wishes to work on the locomotive for a few weeks this summer. We plan to start the installation of all the copper pipe runs. If anyone wishes to help on this work, even for a few days please contact the project office. Your help will be greatly appreciated.

The lubricators we have for the locomotive are similar to those fitted to the Jubilee class locomotives.The system we will fit to The Unknown Warrior will therefore be based on the Jubilee arrangement.

The Lubricators themselves are under overhaul, the 16 feed cylinder lubricator at the Great Central Railway, Loughborough and the smaller 8 feed lubricator for the axleboxes will be done at Llangollen.

The major change from the original Patriots will be the fitting of atomisers for the cylinder and valve lubrication. The oil from the lubricator pumps is passed into the atomiser and mixed with steam to form a mist which them passes into the cylinder block valve chests and bore. The mist distributes more quickly and evenly than plain oil so help spread the lubrication to all parts of the machinery, reducing wear and friction.

The atomisers and associated fittings have been ordered from Tyseley Locomotive Works, who have the castings in stock.


Pistons, Valves and Motion

Work continues at Llangollen towards fitting the Motion Girders to the Frame Assembly.

Once the Cylinder are finally in place fitting the rear covers and slide bars will progress to completion

The Piston castings will be ordered soon.

Manufacture of the Coupling Rod Bushes and Brasses is expected to start soon at Llangollen.

Connecting Rods being worked on in the shed at Llangollen, 2nd April 205..

Photo – Gavin Shell

David Hughes get down to work on the Motion Girder at Llangollen, 2nd April 205..

Photo – Kevin West


Work on assembling the bogie has commenced at Tyseley Locomotives Works. A small amount of remedial work has been required on the Bogie Centre casting, which id due for completion next week. Next stage will be to mount the Frame Plates to the Centre Casting.

The Bogie Frame Assy takes shape at Tyseley Locomotive Works – 2nd June 2015.

The new Bogie Axlebox casting await machining at Tyseley Locomotive Works – 2nd June 2015.

Photos – Kevin West

Machining of the Axle and WheelCenters for the new Bogie Wheelset is underway at Harco Engineering.


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. As reported last month it was decided to replace the original Rear Dragbox with a new fabricated unit. This has now been completed.

Following on from this, cad data and drawings were prepared for the Front Dragbox Assembly and also the remaining parts required for the Frame refurbishment. These have now been passed to Rowlescourt and manufacture of parts is continuing.

Rear Dragbox Assembly.

Photo – Rowlescourt Engineering

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

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