While a lot of the BR diesel classes were ordered straight off the drawing board, there were some prototype locomotives. These included.

LMS 10000 and 10001 (D16/1)

The first two mainline diesel locomotives were built by the London Midland and Scottish Railway in their Derby Plant in 1948 and 1949. While they were not part of the dieselisation era, they were the forerunners for many of the designs. They were inherited by BR and classified as the D16/1 class, and didn’t get a TOPPS number.

Designed by H. G. Ivatt, they used an English Electric engine and electric transmission. EE helped in the design and built process and it is easy to see the likeness between the LMS twins and the latter EE designs, they had similar, if more rounded, snouts to the class 37s.

They weighed in at around 130 tons, but ran with a Co-Co arrangement, so had a large axle loading. While they were certainly big, and at 90mph pretty quick, they were not powerful. They only produced 1600hp, so struggled on heavier trains and often had to work in pairs.

They were withdrawn in the mid 1960s and scrapped a few years after. A group is trying to build a replica of the LMS 10000 using modern parts.

Class D16/2

Three Southern Region diesel prototypes appeared in the early 1950s, having been designed pre-nationalization by Oliver Bulleid, the last Chief Mechanical Engineer of the Southern Railway. Although they also used the EE engine, they were more powerful, with 1750hp for the first 2 and 2000hp for the last one. They were heaver than the LMS engines and ran on an 1Co-Co1 wheel arrangement. Like Bulleid’s electric trains and revolutionary steam Leader design, the D16/2s were flat fronted, basically a wheeled box with two cab windows at either end. They performed well in trials and were used as the engineering basis for the class 40 locomotives. However the locomotives themselves were non-standard and were scrapped in the 1960s.

British Rail 10100

Known as the Fell Diesel, after Lt. Col. Fell, one of the designers, this was an attempt to build a diesel-mechanical locomotive. Built at the old LMS Derby works in 1952, it was another snouted locomotive, but this time the snouts were longer and squarer, giving it more of the look of a cubist crocodile. It produced 2000hp and weighed in at 120 tons, lighter than equivalent locomotives with electrical transmission.

Mechanically it was pretty complicated, with 4 12 cylinder Paxman prime mover engines connected to eight driving wheels. The wheel arrangement was classed as 4-8-4 since it the powered wheels were coupled together with 2 unpowered axles at each end. The engines were connected to each other through differential gearing. The engines ran at near constant speed, with only one engine being connected drive mechanism at low speed and more engines being connected in as the power requirements were increased. Two further 6-cylinder marine engines drove superchargers, so in total there were 60 cylinders at work in the locomotive.

While it was powerful, it did have a major issue, in that half its weight was over unpowered axles, so compared with other locomotives it didn’t have as much adhesion. Everything in the locomotive was mechanically driven which meant that there were lots of long shafts and linkages inside. On top of this, due to the way the six engines worked together to regulate the output torque, it was incredibly loud, especially at startup.

It was withdrawn after a fire at Manchester Central and scraped a few years later in 1960.

British Rail 10800

10800 was a low powered diesel-electric locomotive designed by LMS’s George Ivatt and built for the railway by the North British Locomotive company. However it was finished in 1950, two years after the LMS had been nationalised to become part of British Railways.

With only 870hp, it was designed for lesser duties, and in order to keep it reasonably light, it only had one cab, near one end. The Bo-Bo locomotive weighted 70 tonnes and was sent to the Southern Region for trials. It was the first mixed traffic diesel-electric and was used for both freight and suburban services.

Visibility was an issue, as it had a high bonnet at both ends, so the view from the cab was limited, although about the same as the steam locomotives it replaced.

Trials in the Southern Region were not promising, the locomotive was underpowered, even for relatively light loads, so often lost time on hilly sections and was eventually replaced from passenger working by steam locomotives. While allocated to Norwood depot, it spent much of its time in the works at Brighton being repaired. The Southern Region gave it the nickname, the Wonder Engine, based on the question ‘I wonder if it will work today?’. It was withdrawn in 1959 and then sold to Brush traction who used it, now named Hawk as a test bed for more a new engine and electronics. It was finally retired in 1968 before being used for spares then scrapped.

Despite the problems of the locomotive, it was used as the basis for the class 15 and class 16 locomotives, neither of which were a huge success.

British Rail 11001

The was one of the first mainline diesels on the railway, it was a diesel-mechanical shunter designed by Oliver Bulleid. It used a Paxman engine of 500hp, through a gearbox to six connected wheels, hence it was a 0-6-0 locomotive. Because there were no drivers with experience of diesels on the railway at the time, all the controls were laid out like in a steam locomotive.

It only had a single cab, with a long, low, bonnet at one end. It tipped the scales at 50 tons.

It was completed in 1949 in Ashford and saw duties in the Southern Region mainly shunting and on branch lines. It remained in service for ten years before being withdrawn and scrapped.

18000 and 18100

The internal combustion engine was not the only way of running a locomotive from diesel. Gas-turbine engines are also trialled on the network and it was the Western Region that got to test them.

Although the Western Region were looking to replace their King class steam locomotives on the top expresses, in the late 1940s there was no single diesel locomotive that was anywhere near powerful enough. The Kings produced around 2500hp at the rail, the LMS diesel’s engine made 1600, but much of this was lost in the transmission to give only 1300 for traction. Obviously, this wasn’t going to be much use to for running heavy trains at high speed.

18000 was built in 1949 by Brown, Boveri & Cie. It was a 115 ton A1A-A1A locomotive with simple lines and a three windowed slightly curved front. It was powered by both a small diesel engine and a turbine, designed to run on heavy fuel oil. The small diesel was meant to start the turbine, but it was also used to drive the locomotive, generally to or from the termini. As its aims were to replace the express Kings and Castles, it was dubbed the Kerosene Castle.

Figures have been published for the power outputs and efficiency of the turbine engines, but there is discrepancy as to some of their accuracy. In theory, the turbine produced 10,300hp, with 7800 absorbed by the compressors, leaving around 2500 to be sent to the traction motors. At the rail, it should have had around 2000hp and would have been capable of 90mph.

It had a few major problems. The first was that the heavy fuel oil, chosen for economy, damaged the turbine blades. Light oil was used on start up, however to save on maintenance this became the norm. The aviation fuel was much more expensive. Turbines work best when under full load, when they aren’t, they are nowhere near as efficient. Even with fast timings and heavy trains, there was no need for the turbines to be ran at full power for long, so fuel economy suffered greatly.

18100 appeared from Metropolitan Vickers, Manchester in 1951. It was another gas turbine, this time designed to prioritise power over economy. It ran on aviation kerosene making it far more expensive to run than 18000. It ran with two extra traction motors, giving it a Co-Co layout and a weight of 130 tons. It didn’t have an extra diesel engine, and used battery power to start the turbine.

The official figures show that the turbine in 18100 made 9000hp, of which 3000hp was usable output. This was converted to about 2500hp at the rail. These figure may not have been totally accurate as it suggests that 18100 was more thermally efficient than 18000, which, in practise, was not the case.

18100 had a short working life and was soon retired and converted into a prototype electric locomotive.

British Rail GT3

18000 and 18100 were also known by the designations GT1 and GT2 respectively, standing for Gas Turbine One and Two. GT3 was the third gas turbine prototype, which although the design was started at a similar time to the other two, it took ten years to build. The main reason it took until 1961 for GT3 to emerge from the Vulcan Foundry at Newton-Le-Willows was that technology had moved on so quickly, gas turbines were no longer a priority.

GT3 was a turbine-mechanical locomotive, where the turbine was linked through a flexible transmission to the driving wheels. For a chassis they used something based on a Standard 5 steam locomotive with a 4-6-0 layout, but strengthened to cope with the extra power of the turbine. The locomotive itself looked like a sleek, streamlined steam locomotive with a flattish front and a long body housing the turbine, with a single cab at the back. It was painted in red oxide. There were bulges along the side for the batteries that started the turbine. These batteries charges while the locomotive was running and gave off hydrogen gas, so needed good ventilation. The locomotive itself was rated for 2750hp and weighed 80 tons.

However GT3 was based on a steam locomotive, so didn’t carry its own fuel supply, this was in a 45 ton tender behind it. By it having a tender, it was limited in that it could only travel at speed in one direction, however since the cab was at the back of the main locomotive, visibility in that direction was also limited compared to contemporary express diesels. These express diesels had cabs at both ends, so had no need of the turntables that GT3 relied on.

GT3 was tested on the West Coast mainline in Cumbria and on the Great Central lines near Leicester. It proved capable but very noisy. By now the Vulcan Works had produced the Deltic diesels which were more powerful and had none of the drawbacks of the singled ended GT3, so it was sent back to Vulcan in 1962 then scrapped by 1966.

This wasn’t quiet the end of the story for gas turbines. In general a gas turbine was physically smaller and lighter than a diesel engine of the same power. They had less moving parts so theoretically needed less maintenance and could run on lower grade¹ fuel. They lost efficiency when not at full load, so were fest suited to long high speed runs. Both the British Advanced Passenger Train (ATP) and French TGV prototypes were gas turbines. The Union Pacific in the US ran of fleet of gas turbine locomotives, some as large as 400 tons and with 8000hp. These ran long distance heavy freight services non-stop, powered by leftovers from the petroleum industry. They went out of use as plastics companies started finding uses for the heavy oil causing prices to rise.

DP1

Probably the most aesthetically pleasing of the diesel locomotives to run on the British Rail network, DP1² was the prototype for the Class 55 Type 5s. Powered by 2 deltic engines, it was capable of 3300hp and 100mph. The nature of the horizontally opposed engines and this locomotive are discussed in another entry. It was built in 1955 at the Vulcan Foundry and retired in 1963 to the science museum, it has since moved to the National Railway Museum’s Shilton centre.

DP2

DP2 was another product of the Vulcan Foundry, this time it was a prototype for a new series of Type 4 locomotives. The original Type 4s were all too heavy and so required extra axles which limited their use on tight curves. A new lightweight design was needed that only required the use of 6 axles while maintaining relatively low loadings. Since, in 1962, English Electric’s Vulcan Foundry were in the middle of building a batch of Class 55 Co-Co locomotives, it was decided to use one of these body shells to base the locomotive on.

It was fitted with a 16 cylinder English Electric engine. The use of only one engine compared with two in the Class 55s meant that the DP2 had radiator grills at one end and only one roof fan. The 2700hp machine was originally painted Brunswick Green before being repainted into 2-tone green. The locomotive went on to be tested on the East Coast Mainline where it struggled to maintain the timings of the Deltics due to not having anywhere near as much power. Despite this, it became the mechanical basis for the Class 50 Type 4s. In 1967 DP2 was involved in a serious accident with a freight train and was badly damaged. It was decided that repair was not a viable option, so the locomotive was scrapped and the mechanical parts used as spares.

D0260 LION

Another consortium looking to gain a contract for the lightweight Type 4s was a grouping of Birmingham Railway Carriage and Wagon Company, Sulzer and Associated Electrical Industries. Sulzer provided the engine, a more powerful version of the one used in the Peak Type 4s with 2750hp on tap. AEI provided the electrical equipment and it was built in the Smethwick carriage works of BRC&W.

Wilkes & Ashmore, the British Transport Commission’s design consultants, had given out guidelines about how new locomotives should look. LION was built to many of these so looked similar to the Class 47s which were to succeed it. Where it differed dramatically was in its livery. It was resplendent in a colour scheme of while with gold bands along the side. While this was extremely eye catching, it did mean models train versions of LION tended to look like the owner had neglected to paint it!

It was built in 1962 and was sent for test in the Western Region where it was able to haul 20 coach loads and haul 520 ton trains up the fearsome Lickey Incline from a standing start without assistance, summiting at 20mph. It was easily capable of 100mph.

Its first revenue earning service was on the Western Region, where it was often arriving early having averaged 100mph for large parts of its trips. On the 28th May it was officially handed over to the BTC. By September it was transferred to the Eastern Region’s Finsbury Park depot in London. It was here where it was tested against other prototype the Type 4s: DP2 and Falcon.

BRC&W were already backing away from the rail industry by this point³ and stopped helping with the maintenance of LION. Two serious faults occurred during its time on the Eastern Region, one was a fire and the other was an electrical problem with the generator that also revealed a broken cooling system. LION was withdrawn after this in November 1963.

While it was a successful locomotive in trials and had produced impressive haulage feats, the locomotive was deemed too complicated to base a class of production locomotives on. By the time it was withdrawn, the order for new Type 4s had gone to Brush. Although these class 47s looked similar to LION and featured the same engine, LION was not a prototype of the class.

AEI reclaimed there electrical equipment, and Sulzer reconditioned the engine and radiators and installed them into a production class 47, however the exact fate of the body was a bit of a mystery. BRC&W didn’t want anything to do with it, and their workforce were not even told about the method of its disposal. It was sold to T.W.Ward’s scrap yard and was broken up at an unknown time.

D0280 FALCON

Falcon, which was the sole member of class 53, was Brush’s prototype for the new lightweight Type 4s. Brush’s approach was to match two high revving Maybach MD655 engines with their own electrical equipment and motors. The resulting locomotive had 2880hp but had an axle loading fractionally above the 19 ton limit that was set in the design criteria. In contrast, LION was on the target and DP2 was a ton and a half below.

Designed to the same guidelines as LION, Falcon looked similar externally except for more radiator grilles on its flanks. It emerged from Brush’s Loughborough works in 1961 and did its first trials on a trip into Derbyshire. In October it was handed over to the Doncaster depot for more trials on the Eastern Region and then was transferred to Finsbury Park. It hauled trains out of both Kings Cross and Liverpool Street.

By December it was taken over to the Western Region where it was used in comparison trials on the Lickey Incline against its resident powerful steam locomotive. Where the steam locomotive struggled and had to be assisted, Falcon handled heavy trains from a standing start with ease. Other trials were successfully performed when working on just one engine and when pulling loads over the maximum allowed for that section of line. On level track Falcon was able to hit it 100mph.

After trials, it was then sent to Sheffield’s Eastern Region depot where it worked a mix between passenger services to London and heavy freight workings. By the end of 1963, it had notched up 125,000 miles of running. By that time it was decided that its trial period was over, but since Falcon was a long way from being life expired, British Rail agreed to hire it back from Brush. It had achieved impressive reliability so far in its life, although some of that was attributable to many of its workings being diagrammed for steam locomotives or lesser diesels so didn’t require all of Falcon’s power. Another reason could be that Brush personnel were very attentive to Falcon and it saw a lot more checks than it would have if it were a British Rail machine.

After hire from Brush it went back to the Western Region, where the depots were used to the Maybach power supplies. It was now used on workings meant for the Type 4 Westerns, which required fast running with heavy loads. It suffered a number of problems including a broken boiler and failed con-rods. When working well, like in 1968, it was able to accumulate more mileage than the average Western. The issue of its future arose in late 1968, when British rail started on its plan to cut down the classes on non-standard locomotives, of which the Falcon was certainly one. It had also been built with vacuum braking equipment, but the new British Rail MK II coaches were all air braked.

It was a surprise then when British Rail actually purchased Falcon from Brush and refurbished it, giving it air brakes and new numbers and paint. However its return to passenger service was short lived. The early 1970s saw the arrival of air conditioned coaches, which needed locomotives fitted with electric train heating. Falcon only had a steam heating boiler. By 1973, Falcon had had its boiler isolated and it was working iron ore trains in the Welsh Valleys. Falcon suffered a traction motor failure in 1975 and was sold for scrap, being destroyed within a few days of arrival at the scrap yard. While preservationists wanted to save it, it was part of the purchase agreement with Brush that British Rail could not sell it on.

The original livery for Falcon was lime green with darker banding at the top and bottom of the body. A large falcon logo was emblazoned on the side. This was changed to brown banding during its first repaint, where it also got a given a yellow nose. Moving to the Western region, it was repainted in the darker Brunswick Green. Finally it got the British Rail blue livery.

The Falcon crest was the source of a number of small mysteries. On scrapping, one of the pair was taken by the National Railway Museum, the other bought by a collector. However, something remarkable similar was found on sale on an Internet auction site purporting to be a piece of Nazi memorabilia. Another one turned up in 2007 on the side of a High Speed Train.

HS4000 Kestrel

The most powerful diesel locomotive to run on British Rail was Brush’s prototype to see the extent of what could be achieved with a Sulzer power supply. It was hoped that this technology demonstrate would attract orders from both the domestic and foreign markets⁴.

Instead of the parallel banked Sulzer engine that had worked well in many Type 4s, Brush went with their sixteen cylinder V engine, built at Winterthur. The V engine was more powerful and since it only had one crankshaft, offered a better power to weight ratio. The Kestrel itself made use of a stress skinned construction and although it looked similar to the Class 47s, LION and Falcon, but it was more streamlined, with curves instead of straight edges.

It was 136 tons and had a Co-Co arrangement, but this actually put the locomotive above British Rail’s desired maximum axle loading of 21 tons. It was completed in 1967 and painted in a scheme of ochre with brown banding. It was sent to work with both heavy mineral trains and passenger services. While it was theoretical capable of 125mph, its heavy weight ruled out fast operation.

In 1969 it was fitted with bogies from a class 47, which although the smaller traction motors reduced its continuous power rating, the lighter weight allowed faster workings. It still, however, didn’t go below the magic 21 tons per axle.

While it proved easily able to handle huge mineral trains on its own, and to at least match Deltic timings on expresses, there was no real call for a locomotive as powerful as Kestrel, especially one as heavy. In 1971, it had its old bogies given back to it and was shipped to Russia for a new life in the Soviet Union.

After testing, the engine was removed and it was filled with concrete used as a static load for testing other locomotives. Kestrel was too small for the Russian loading gauge, which mean that some signals were not visible to the drivers. Also it meant that internal passages were too small compared with the much larger locomotives that Russian crews were used to. Finally there was the issue of the Stressed Skin construction that mean as it started to corrode, the locomotive lost integrity.

The remains were scrapped in 1993.