Steam Locomotive Restoration of Merchant Navy 35011

I’m pleased to be able to welcome back as guest blogger Simon Shutt to give an update on the steam locomotive restoration of Merchant Navy locomotive 35011 General Steam Navigation

Since the first report on this steam locomotive restoration, the Society has made excellent progress towards returning 35011 to her pre-rebuilding condition.

Locomotive Nameplates

Volunteers with nameplates

One of the highlights of the past year has been the successful purchase of the name plates for the locomotive thanks to the kind sponsorship by our members. Two nameplates have been produced and have been painted differently in order to reflect both possible liveries of the finished locomotive. The red backed coloured nameplate was used with the original locomotive Malachite green livery as well as Southern Railway wartime black and British Railways express blue liveries. A second nameplate has been finished with a black background a version which adorned the British Railways Brunswick green. The Society exhibited the black nameplate alongside the locomotive at the Sellindge site in early May 2018. This together with a freshly painted General Steam Navigation locomotive and happy volunteers presented a credible image to the Heritage Community of the Societies intentions to restore 35011

Steam Reverser

Back in the summer of 2017 the Society purchased a virtually complete Bulleid designed steam reverser.
The majority of components for the steam reverser assembly have now been procured with only some easily manufactured cab controls now required. The selection of these components was earmarked from the beginning as a high priority purchase given it’s one of the few items that hasn’t been manufactured during the preservation era. The reverser is the first major part that society has purchased for the valve gear arrangement that will control General Steam Navigation. The Bulleid designed steam reverser had a bad reputation during British Railways operation but the preservation era has proved it is a reliable design if it is maintained correctly. For example replacing the piston seals in the oil cylinder at the first sign of leakage. The reverser components are all in good condition and will only need some light overhaul work to make them suitable for use on 35011.

Trailing Truck

Much of the work in 2018 has focused around the trailing truck. Our goal is to obtain all the components by the end of the year to facilitate a quick overhaul.

When General Steam Navigation was at Barry Scrapyard she was seen as beyond repair primarily because of the replacement of the middle driving wheelset with a plain axle wheelset by British Railways just prior to its sale to Woodham’s. As a result during its time there numerous components were removed for other projects. Fortunately the society’s tenacity has been rewarded with the majority of parts required for the trailing truck having been obtained some of which are newly manufactured.

Once work started on 35011’s trailing truck it generated some debate within the membership over whether to replace the fabricated design of trailing truck she is currently fitted with, for the earlier cast version, that could be available from one of the other surviving Merchant Navy locomotives. The first 20 Merchant Navy locomotives, including of course General Steam Navigation, were built with a cast trailing truck. Subsequently, to save weight, a fabricated version was designed and produced. The first of these fabricated trailing trucks was fitted to 21C21 New Zealand Line followed by remaining 9 new build Merchant Navies.

Comparison photo of the 2 types of trailing truck. Top is 35006 below is ours.

In subsequent years during heavy intermediate overhaul of these locomotives at Eastleigh Works fabricated and cast versions exchange was not uncommon. Records show that of the first 20 Merchant Navies that were built with cast trailing trucks 35002, 3, 4, 11, 14, 17 and 19 were fitted with the fabricated type.

The Society has researched when 35011 may have been fitted and believe that the exchange probably occurred during its overhaul between 25 January 1955 and 19 February 1955. Photographs taken of the locomotive around this time does show it fitted with a fabricated truck.

Incredibly of the remaining Merchant Navies the only one with a fabricated trailing truck is General Steam Navigation. This gives the engine another unique feature when compared to her sisters. So this together with the costs associated with replacing the fabricated version with the cast one has led to the conclusion that money would be better spent on restoring other areas of the 35011.

The first purchases for the trailing truck were the oil box keeps that sit in the axle box.

Various new components for the Trailing Truck

The keeps were cast using patterns held by the Mid-Hants Railway. They had produced them for castings to be used on their own locomotive. To reduce costs it was decided by the Mid-Hants to cast the keeps in brass rather than aluminium. This material wasn’t available during the second war as it was a key strategic metal used for example in the construction of aircraft. So the Mid-Hants Railway revised the original pattern drawings and successfully had the material change approved for their locomotives.

To reduce future costs we took the decision to also have the keeps for the trailing truck cast in the same batch as those for the Mid-Hants Railway. The keeps will require some machining before they are ready to be trial fitted to the bogie.

The society has also had cast a pair of axle box covers for the trailing truck. The covers have been cast from a pattern made from a cover loaned to us by the Merchant Navy Locomotive Preservation Society.

Casting Marks

MN 35011 outside Eastleigh Works

As well as the cost saving, using one of Clan Lines covers meant we were also able to feature Eastleigh Works casting marks which are very prominent on the finished covers. These marks are a small piece of detail that will improve both the overall look of the cover and the locomotive. The dimensions for the lettering aren’t featured on the drawings and would have been very difficult to recreate without the use of an existing cover. The freshly cast covers have now been machined. The fixing holes have been drilled out and the rear face milled flat as well as some fettling up as required.

To complement the fabricated training truck covers the Society has also ordered matching fabricated dust covers for the spring beams. With the drawings for the cast versions not being available the Society decided to go ahead with the fabricated design which would improve the uniqueness of the locomotive. The alternative would be to go down the extremely costly production route of borrowing an existing cover to use to make a pattern, then have castings made which would then have to be machined. The drawings for the fabricated dust covers were converted into a CAD file which enabled the pieces to be laser cut and then welded together. This work was done by N.B. Engineering Services in Darlington. The two dust covers were completed in time to be taken down to the working party over the 2018 May Bank holiday and were successfully test fitted to the locomotive.

Spring Beams

The biggest challenge faced with a trailing truck will be the spring beams. These were traditionally created by forging steel into the correct shape and then machining the piece to the required dimensions. With the introduction of water jet cutting they have been cut out of a block of steel and then machined.

Spring Beam being machined

These spring beams will have the same strength as the forged version but for around half the price. One of our volunteers, James Pierce, converted the drawings into a CAD file. This was sent directly to the water jet company. Water cutting of beams is a common practice that has been used on recent locomotive restorations, although General Steam Navigation will be the first Bulleid locomotive to feature spring beams produced in this way. If found necessary certification for main line from a nine running could be obtained. The previous owner 35011 purchased a complete new set of springs for the trailing truck so we only require the spring hangers and the various attached fittings. One of our members Mr Tony Simmons has kindly offered to machine these for us.

Replacement of Flawed Centre Axle

In July 2017 the middle wheelset with the flawed plain axle that had come from 34046 Braunton arrived safely at the South Devon Railway engineering workshops. An examination has been carried out of the Firth Brown wheel centres and have been found to be in excellent condition. A new set of tyres will be required on the finished wheel set but these are readily available. At this stage the old tyres will remain on the wheels as this type of wheel centre have a tendency to warp if left without a tyre on them for a long length of time.

The axle and coupling rod crank pins have now been released from the Firth Brown wheels. The South Devon Railway engineers achieved this by drilling a hole through the middle which allowed them to oxy/acetylene burn out around 80% of the axle and crank pins in turn. Then as the remaining metal cooled down the axle and crank pins were released from the wheel centre leaving the wheel pans undamaged suitable for fitting to the new crank axle when it is made.

Share in our success

General Steam Navigation at Salisbury circa 1957

The Society has over forty per cent of the funds required for the construction of a new crank axle with more being added each month by standing order. This is will be a very significant hurdle in the restoration of 35011 and a very exciting one. You too can share in this excitement by making a contribution towards this cranked wheel set. The Heritage Railway movement has achieved massive goals over the decades which has resulted in the return to service of the giants of steam such as 71000 Duke of Gloucester once considered ‘mission impossible’. 35011 General Steam Navigation’s biggest hurdle has to be this cranked middle axle so please join the society for £10 a year and donating time or money. Purchasing shares will make you feel even more part of the success in the locomotive. You can find out more information on our website. Together we can put the steam back into General Steam Navigation.