LMS Princess Royal Class ‘Turbomotive’ No. 6202

The LMS Princess Royal Class ‘Turbomotive’ No. 6202 was a unique experimental steam locomotive that was modified to include turbine generators instead of cylinders. As Chief Mechanical Engineer of the LMS during the 1930s, Sir William Stanier wanted to incorporate a steam locomotive into the LMS fleet that would innovate the British rail industry. Inspired by the 1920s built Swedish Ljungström locomotives, he deemed the Princess Royal Class to be suitable for a new type of steam locomotive. The main frame and wheel set became the basis for this locomotive. The third Princess Royal Class locomotive to be constructed was chosen to be the test bed and was outshopped in June 1935 as No. 6202 with an LMS Crimson Lake livery.

Not long after, the ’Turbomotive’ was seen in service hauling passenger stock on the main line between London and Liverpool. Between the years of 1936 and 1945, more than 300,000 miles had been covered on the main line. When Britain’s railways were nationalised in 1948, the LMS Crimson Lake livery was changed to a BR Black livery. To further reflect nationalisation, the LMS legend on the side of the tender was replaced with the BR crest and the number was changed to No. 46202.

In 1949, a serious turbine failure occurred. The expensive repair costs amidst a background of post Second World War austerity and material shortages made it abundantly clear that the appropriate repairs were uneconomical. The locomotive was taken out of service, and it was decided that it would be rebuilt into a conventional steam engine. In August 1952, No. 46202 entered service as a conventional steam locomotive with a Duchess cylinder arrangement and named ‘Princess Anne’.

Only a mere two months later, on 8 October 1952, ‘Princess Anne’ became involved in the horrific rail disaster at Harrow and Wealdstone where three passenger trains collided. At 8.19am, the Duchess Pacific No. 46242 ‘City of Glasgow’ initially collided with a passenger service train from Tring to Euston which was transporting early morning commuters. ‘City of Glasgow’ had been travelling from Perth to Euston. ‘Princess Anne’ then ploughed into the wreckage left behind on the track and a total of 112 people tragically passed away because of the crash. ‘Princess Anne’ was taken to Crewe for examination and was deemed to be damaged beyond repair. The locomotive was scrapped on 22 May 1954.

Sir William Stanier’s special turbine Pacific proved to be excellent in service by continuously hauling passenger trains on the main line. Stanier left behind a legacy of a successful experiment in making a faster and more efficient locomotive.

Features of the LMS Princess Royal Class ‘Turbomotive’

The ‘Turbomotive’ was a non-condensing steam turbine locomotive. What made the locomotive so unique was that turbines were incorporated instead of the usual cylinders. Two turbines were housed in the locomotive: a large turbine on the left for forward motion and a small turbine on the right for reverse running. Eighteen rows of blading were included in the large turbine whereas there were only four rows of blades in the small turbine. The large turbine enabled the locomotive to produce 2400hp at over 7000rpm, along with a steam pressure of 250lb. Six separate steam nozzles were included that controlled the power output where each nozzle could be individually opened or closed.

A disadvantage to the turbine system was that the smaller reversed turbine did not have enough power and was not strong enough to reverse if the locomotive was connected to a heavy rake of coaches. Due to this, the ‘Turbomotive’ always had to be facing forward when hauling passenger trains.

A double blastpipe and chimney was fitted due to the low-pressure exhaust. Despite this, smoke drift was still a problem in certain weather conditions. To solve this, smoke deflectors were fitted in 1939. These additions enabled for a smoother running on the track and the use of coal was more economical. Compared to the sharp exhaust blast from a conventional steam locomotive, the double chimney had a continuous exhaust stream.

‘Turbomotive’ Final Sample

Two ‘Turbomotive’ final samples arrived for us to examine in this month’s Engine Shed blog. For such a unique locomotive, we thought it best for the models to not only depict the prototypical locomotive at different stages, but we also thought it prudent that there should be two models that are sound fitted.

Two models represent the prototypical locomotive at various stages of its working life. The first model is representative of the ‘Turbomotive’ as being under LMS service and numbered as No. 6202. Each model comes complete with a vivid LMS Crimson livery including the sound fitted version. As for the second model, this represents the locomotive under BR ownership and was renumbered to No. 46202. A modest, no-nonsense BR Black livery with an early BR crest has been applied to the model. A sound fitted version of the BR representative model will also be available.

Please find below images of the LMS Princess Royal Class ‘Turbomotive’ No. 6202 with the tender included.  

Non-Sound Fitted Version | Sound Fitted Version

You will also find images of our replication of the overhauled BR Princess Royal Class ‘Turbomotive’ No. 46202 below.

Non-Sound Fitted Version | Sound Fitted Version

Features of Hornby’s ‘Turbomotive’ Model

Following on from the Turbocharge and Boulevard blog where the engineering sample was showcased, we will reiterate certain features already mentioned. The ‘Turbomotive’ is the heaviest steam locomotive model ever made by us. Our hefty model weighs in at an astonishing 589g, over half a kilo! This is due to the locomotive’s body being formed from diecast, particularly the running plate, chassis, and the locomotive’s boiler.

A radiator flap, a rectangular etched metal piece on our model, will be hinged and can be moved according to your preference. This can be observed visually on the Engine Shed cover image. The radiator flap is located just below the smokebox door and above a mesh grille. On the prototypical locomotive, air cooling was a requirement for the oil lubricator pump to work efficiently. Air intake flowed through the grille with the purpose of the radiator flap being to force as much air as possible through the grille by the top flap raising up on hinges. Air would reach the oil lubricator pump for it to cool down. The fall plate on the model is also hinged.

Some more typical features to point out here are the authentic flickering firebox, sprung buffers, and a sliding roof vent above the cab which can be moved as you see fit.

Class 755 ‘Flirt’ Running Sample

Back in May’s edition of Engine Shed, Streamlined ‘Salmon’ Wagon, the Class 755/3 and Class 755/4 ‘Flirt’ test shots from the mould tools were shown for the first time. Unfortunately, the running sample did not arrive in time for the June edition, but it has now arrived in Westwood and can be shown in this August edition. Please find below the images of the running sample.

The running sample’s performance was about 20% slower than we would have liked when tested on the track. Ideally, a smooth and fast running around the track would occur, particularly around the curves and gradients. This will, of course, be amended through further tests and studying of the sample. Please note the following caveat that this is not the final sample and is still going through the development process.

It's time to sign off on another edition of Engine Shed. We've had fun bringing you model updates at Engine Shed - thank you for reading! If you have any queries or comments, feel free to email marketing@hornby.com and we'll be in touch soon. See you next month!

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Happy Modelling!

The Engine Shed Team

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