British Rail 10100
Encyclopedia
British Railways 10100 was an unusual experimental diesel locomotive
known informally as The Fell Diesel Locomotive (after Lt. Col. L.F.R. Fell, who was one of the designers). It was the joint production of Davey Paxman & Co
, Shell Refining & Marketing Co and Lt-Col L.F.R. Fell, built for them by the London, Midland and Scottish Railway
at Derby
. Sir Harry Ricardo
was also involved. By the time it emerged in 1950, nationalisation had taken place and it carried British Railways livery. The locomotive had six diesel engines, four of them used for traction. There were two auxiliary engines, both of which were 150 hp AEC 6-cylinder units, and these drove the pressure-chargers
for the main engines and the purpose of this arrangement was to enable the main engines to deliver very high torque
at low crankshaft speed.
gearing to transmit the power, it was originally built as a 4-8-4 with the coupling rods connecting the centre four pairs of driving wheels. It was modified to 4-4+4-4. At 2000 hp it was the most powerful of BR's locomotives at the time. From 1951 it worked the expresses from Manchester to London, proving some 25% more powerful than 5XP 4-6-0
s. While the mechanical transmission made it much lighter than the diesel-electric locomotives, its complicated mechanism made it difficult to maintain (a working model of the transmission is on display at the National Railway Museum
, York).
The locomotive had four main engines. Each engine was connected to the gearbox via a hydraulic coupling, which could be filled with oil to transmit power or drained of oil to disconnect that engine from the transmission. One-way clutches prevented rotation of the input shafts when the couplings were drained. The engine outputs were combined in pairs by two sets of differential gearing, and the output shafts from these two gearsets were then combined by a third differential gearset to drive the main output shaft.
The effect of this arrangement was that the gear ratio between an engine and the output shaft depended on how many engines were driving the transmission. Gear ratio selection was accomplished not by "changing gear" in the conventional sense, but by filling or draining the hydraulic couplings to connect or disconnect the engines from the transmission. With only one hydraulic coupling filled with oil and the other three engines disconnected and their respective input shafts to the transmission locked by the one-way clutches, the single engine drove the output shaft through an effective gear ratio of 4:1. With two engines driving, the effective gear ratio was 2:1; with three engines, 1.33:1; and with all four engines, unity. In other words, the effective gear ratio of the transmission was the inverse of the number of engines driving it.
It can be seen from this that unlike the transmission of a car, there was no overall torque-multiplication effect from selecting a lower gear. The 4:1 mechanical advantage afforded to the single engine driving in first gear was cancelled out by the fact that there was only one engine operating, so the maximum output torque from the transmission was the same as was available in top gear with all four engines operating. The same argument applies to second and third gears. The transmission of this locomotive, therefore, unlike almost all other locomotive transmissions, did not provide any means of matching the torque characteristics of the engine(s) to the requirements of the locomotive; it did not provide for an increased torque output at low speeds for starting and hill climbing. It served only to match the output speed of the engine(s) to the requirements of the locomotive.
The requirement for high starting torque was met in the Fell not by the transmission characteristics but by altering the torque characteristics of the engines themselves. Normally a diesel engine aspires charge at a mass flow rate proportional to its rotational speed; the faster it rotates, the more charge it can aspire, and this leads to a power output curve which rises more or less linearly with rotational speed until various limiting factors become significant.
In the Fell locomotive, however, the four main drive engines received their charge from Roots blowers driven by two further auxiliary engines which were governed such that when the traction power demand was more than minimal, they operated at essentially a constant speed. Since a Roots blower is a positive-displacement device, this meant that the mass flow rate at which charge was delivered to the main engines depended not on the speed of the main engines but on that of the auxiliary engines, so the power output of the main engines was essentially defined by the speed of the auxiliary engines.
Since the speed of the auxiliary engines was held constant, the main engines had a power curve which was constant with rotational speed; since power is the product of torque and rotational speed, the main engines were endowed with a torque curve inversely proportional to speed, producing maximum torque at a low speed and reducing as the speed increased. Thus was provided the necessary increased low-speed torque output for starting and hill climbing.
in June 1960.
Diesel locomotive
A diesel locomotive is a type of railroad locomotive in which the prime mover is a diesel engine, a reciprocating engine operating on the Diesel cycle as invented by Dr. Rudolf Diesel...
known informally as The Fell Diesel Locomotive (after Lt. Col. L.F.R. Fell, who was one of the designers). It was the joint production of Davey Paxman & Co
Paxman (engines)
Paxman is a major British brand of diesel engines. Ownership has changed on a number of occasions since the company's formation in 1865, and now the brand is owned by MAN SE, as part of MAN Diesel & Turbo. At its peak, the Paxman works covered 23 acres and employed over 2,000 people. Engine...
, Shell Refining & Marketing Co and Lt-Col L.F.R. Fell, built for them by the London, Midland and Scottish Railway
London, Midland and Scottish Railway
The London Midland and Scottish Railway was a British railway company. It was formed on 1 January 1923 under the Railways Act of 1921, which required the grouping of over 120 separate railway companies into just four...
at Derby
Derby Works
The Midland Railway Locomotive Works, known locally as "the loco" comprised a number of British manufacturing facilities in Derby building locomotives and, initially, rolling stock in Derby, UK.-Early days:...
. Sir Harry Ricardo
Harry Ricardo
Sir Harry Ricardo was one of the foremost engine designers and researchers in the early years of the development of the internal combustion engine....
was also involved. By the time it emerged in 1950, nationalisation had taken place and it carried British Railways livery. The locomotive had six diesel engines, four of them used for traction. There were two auxiliary engines, both of which were 150 hp AEC 6-cylinder units, and these drove the pressure-chargers
Supercharger
A supercharger is an air compressor used for forced induction of an internal combustion engine.The greater mass flow-rate provides more oxygen to support combustion than would be available in a naturally aspirated engine, which allows more fuel to be burned and more work to be done per cycle,...
for the main engines and the purpose of this arrangement was to enable the main engines to deliver very high torque
Torque
Torque, moment or moment of force , is the tendency of a force to rotate an object about an axis, fulcrum, or pivot. Just as a force is a push or a pull, a torque can be thought of as a twist....
at low crankshaft speed.
Design
The design for 10100, a collaboration between Fell Developments Ltd and H. G. Ivatt of the LMS, aimed to address several of the weaknesses perceived of diesel powered rail traction. Weight was reduced by using several small engines, meaning that both the engines and their supporting structure could be lighter. This was also expected to save time in maintenance as an individual diesel could be exchanged more easily and with lighter equipment.Transmission
Using differentialDifferential (mechanics)
A differential is a device, usually, but not necessarily, employing gears, capable of transmitting torque and rotation through three shafts, almost always used in one of two ways: in one way, it receives one input and provides two outputs—this is found in most automobiles—and in the other way, it...
gearing to transmit the power, it was originally built as a 4-8-4 with the coupling rods connecting the centre four pairs of driving wheels. It was modified to 4-4+4-4. At 2000 hp it was the most powerful of BR's locomotives at the time. From 1951 it worked the expresses from Manchester to London, proving some 25% more powerful than 5XP 4-6-0
4-6-0
Under the Whyte notation for the classification of steam locomotives, 4-6-0 represents the wheel arrangement of four leading wheels on two axles in a leading truck, six powered and coupled driving wheels on three axles, and no trailing wheels. This wheel arrangement became the second-most popular...
s. While the mechanical transmission made it much lighter than the diesel-electric locomotives, its complicated mechanism made it difficult to maintain (a working model of the transmission is on display at the National Railway Museum
National Railway Museum
The National Railway Museum is a museum in York forming part of the British National Museum of Science and Industry and telling the story of rail transport in Britain and its impact on society. It has won many awards, including the European Museum of the Year Award in 2001...
, York).
The locomotive had four main engines. Each engine was connected to the gearbox via a hydraulic coupling, which could be filled with oil to transmit power or drained of oil to disconnect that engine from the transmission. One-way clutches prevented rotation of the input shafts when the couplings were drained. The engine outputs were combined in pairs by two sets of differential gearing, and the output shafts from these two gearsets were then combined by a third differential gearset to drive the main output shaft.
The effect of this arrangement was that the gear ratio between an engine and the output shaft depended on how many engines were driving the transmission. Gear ratio selection was accomplished not by "changing gear" in the conventional sense, but by filling or draining the hydraulic couplings to connect or disconnect the engines from the transmission. With only one hydraulic coupling filled with oil and the other three engines disconnected and their respective input shafts to the transmission locked by the one-way clutches, the single engine drove the output shaft through an effective gear ratio of 4:1. With two engines driving, the effective gear ratio was 2:1; with three engines, 1.33:1; and with all four engines, unity. In other words, the effective gear ratio of the transmission was the inverse of the number of engines driving it.
It can be seen from this that unlike the transmission of a car, there was no overall torque-multiplication effect from selecting a lower gear. The 4:1 mechanical advantage afforded to the single engine driving in first gear was cancelled out by the fact that there was only one engine operating, so the maximum output torque from the transmission was the same as was available in top gear with all four engines operating. The same argument applies to second and third gears. The transmission of this locomotive, therefore, unlike almost all other locomotive transmissions, did not provide any means of matching the torque characteristics of the engine(s) to the requirements of the locomotive; it did not provide for an increased torque output at low speeds for starting and hill climbing. It served only to match the output speed of the engine(s) to the requirements of the locomotive.
The requirement for high starting torque was met in the Fell not by the transmission characteristics but by altering the torque characteristics of the engines themselves. Normally a diesel engine aspires charge at a mass flow rate proportional to its rotational speed; the faster it rotates, the more charge it can aspire, and this leads to a power output curve which rises more or less linearly with rotational speed until various limiting factors become significant.
In the Fell locomotive, however, the four main drive engines received their charge from Roots blowers driven by two further auxiliary engines which were governed such that when the traction power demand was more than minimal, they operated at essentially a constant speed. Since a Roots blower is a positive-displacement device, this meant that the mass flow rate at which charge was delivered to the main engines depended not on the speed of the main engines but on that of the auxiliary engines, so the power output of the main engines was essentially defined by the speed of the auxiliary engines.
Since the speed of the auxiliary engines was held constant, the main engines had a power curve which was constant with rotational speed; since power is the product of torque and rotational speed, the main engines were endowed with a torque curve inversely proportional to speed, producing maximum torque at a low speed and reducing as the speed increased. Thus was provided the necessary increased low-speed torque output for starting and hill climbing.
Withdrawal
It was withdrawn after a serious fire at Manchester. The industrial consortium sold it to British Railways in 1955 for whom it remained in service until 1958 when it was withdrawn after sustaining accidental damage to the main gearbox. It was allocated to Derby and it was broken up at BR Derby WorksDerby Works
The Midland Railway Locomotive Works, known locally as "the loco" comprised a number of British manufacturing facilities in Derby building locomotives and, initially, rolling stock in Derby, UK.-Early days:...
in June 1960.