Lion locomotive

Generators
The generator group consisted of three machines - train heating, traction, and low tension auxiliary generators - arranged in tandem and direct-driven from the output shaft of the diesel engine synchronising gears. The traction and train heating generators were built in a common frame, the latter machine being nearer to the diesel engine. Their armatures were mounted on the common shaft which was supported by a single bearing located in the traction generator endshield. The auxiliary generator is overhung from the traction generator, its armature being assembled on an extension of the main shaft. All three machines had British standard Class H insulation throughout.
The traction generator supplied power, under automatic control of a load regulator to the six traction motors, connected permanently in parallel. The machine embodied a separately excited field winding whose field strength was adjusted by the load regulator. A distinguishing feature of this generator was the series field winding, the design of which was the subject of a patent application. The winding consisted of bars fitted in the main pole faces connected in series to bars clamped on one side of the interpoles, and formed into two parallel paths in series with the armature.
The current in this winding produced the necessary decompounding field which, in conjunction with the separately-excited field, gave the required output characteristic; it also provided the flux for the commutating field and compensation of armature reaction. The same winding also served as a starting winding when motoring the generator from the battery to start the diesel engines.
This design of winding allowed a saving on copper and space to be made, enabling a larger diameter and consequently shorter armature to be built within the permissible limit of overall frame diameter.
Another noteworthy feature of this machine was the arrangement of the armature winding. This was of the radial type in which each conductor was placed so that it occupied the full width of the armature slot, thereby minimising the eddy current losses and improving the space factor compared with the conventional "side-by-side2 winding. Cooling air was arranged to pass between the risers connecting the commutator with the armature coils. The design allowed a high continuous rating current to be achieved
"Pollock" type commutators were fitted to both the traction and train heating generators. The advantages included radial stability of the copper segments which were clamped throughout their length, reduced length of segment because the creepage distances were vertical to the machine axis, and reduced quantity of copper resulting in an appreciable saving in weight. The brushgear of the train heating generator was retractable to facilitate inspection and maintenance.
The three generators were continuously rated in accordance with BS 173/1960 as follows:

Traction Motors
The six traction motors were the first of the new AEI type 253 machines to be used on British Railways: this type was also fitted to the recently ordered type2 1250 hp locomotives which were to be built in the Railways' workshops during 1962.
The motor had been developed to cover a wide range of traction applications, and was particularly suitable to diesel-electric locomotives. In this instance, with two stages of field weakening and in conjunction with a 17/70 gear ratio, the motor gave a maximum service speed of 100mph.
Each motor was of the nose-suspended, axel-hung type, force ventilated and equipped with a lap-wound armature. The axle-suspension bearings were of the sleeve type with felt-pad lubrication. The motor nose was supported from the bogie transom by a rubber bonded sandwich mounting arranged so that the rubber was always loaded in compression irrespective of the direction of travel.
On outstanding feature of the motor was its small volume and consequent low weight in relation to its high torque and power output. This resulted in the use throughout of silicone-treated insulation to British standard Class H specification and from the particular attention given to the problem of cooling, both of which ensured a long and trouble-free life.
A radial type armature winding, similar to that used in the traction generator, had been adopted and this, together with other features, assisted in the transferee of heat from the windings.
Steel slot wedges were, among other measures, used to ensure that the armature coils were held rigidly in position.
Various features were introduced to facilitate maintenance. They included grease relief valves which prevented over greasing of the armature roller bearings, removable brush guides which could be easily and cheaply replaced when worn, and PTFE insulating sleeves on the brush gear support pins to provide a clean, non-tracking, and unbreakable insulation.
The continuous ratings of the motor to BS.173/1960 were as follows:

Control Equipment
The control scheme was based on those successfully used in the large number of British Railways Type 3 locomotives of 1160 and 1250 hp. fitted with AEI/Sulzer power equipment but modified in certain important respects to meet the additional requirements of the locomotive.
The main modifications resulted in the fitting of equipment for electric train heating, the power for which was supplied at 800V DC. Advantage was taken of the availability of the 800V generator to use it for supplying not only the train heating load, but also the radiator fan and traction motor blower motors, and the traction generator field excitation. Including this excitation circuit in the 800V system allowed reduced currents to be handled by the load regulator.
In line with standard B.R. practice for diesel-electric locomotives, the diesel engine speed is controlled by variations of air pressure initiated by movement of the master controller between its "OFF" and "FULL" positions. An additional spring-loaded "TOP" position was provided so that, when the handle was moved to this position, either electric train heating was cut off and the power thus available was transferred to traction, or, if electric train heating was not in use, the engine speed was raised to give a corresponding increase in power output for traction purposes.
Duplication of driver's controls for the two methods of train heating was avoided by installing a selector switch which could be set for whichever heating system was required. The design of the controls for the steam train heating boiler and the train heating generator permitted automatic operation of the apparatus once switched on.
The greater part of the control equipment was housed in a cubicle installed in the locomotive as a prewired sub-assembly. The electric motor-driven load regulator, its associated generator field resistors, and certain other resistors were mounted in a compartment built into the removable roof-section above the auxiliary machines at No. 2 end of the locomotive. These resistors were cooled by natural ventilation.
Each cab contained a full set of driving controls, instruments, and indicator lights; a detailed description is given in section "Cab Equipment".

Auxiliary Machines
The auxiliary machines were separated electrically into two groups, viz, (1) those deriving their power from the 800V train heating generator, and (2) those supplied from the 110V auxiliary generator. Included in the 800V category were the two radiator fan motors of 26.8 hp each, and the two 7.8 hp motors for the centrifugal traction motor blowers. These motors were arranged for either series or parallel operation depending upon the output required from the power unit. By this means, the noise produced by these auxiliaries were considerably reduced when the locomotive was operating at low power - such as within station confines.
The remaining auxiliaries, which operated from the 110V system, comprised four machines. They included a combined pump set, consisting of a 15 hp motor directly driving the water-circulating pump, and, through a gear-box, the fuel transfer pump and the auxiliary lubricating oil pump; two Northey type 125 RE/FM two-speed rotary exhausters, each driven by a flange-mounted motor, for the vacuum brake system; and a Westinghouse type 2EC 38B compressor, which supplied air at 100lb. per sq. in for the air brake system and for operation of various components of the control equipment.

The Sulzer type 12 LDA28C engine was the latest development in the LDA range of engines, and, with a continuous output of 2750 hp was the most powerful rail-traction diesel engine in Western Europe. It was the successor of the type 12 LDA28B engine already installed in upwards of 200 Type 4 locomotives on British Railways. As the latter engine is well known it is only necessary to describe the new features incorporated in the "C" version of the engine.
The increased output was obtained by improving the intercooling system and raising the nominal crankshaft speed, while the b.e.m.p. had been slightly increased from 163 to 168 lb. per sq in.
The full-load crankshaft speed was now 800rpm compared with 750rpm in the previous engine, but the re-design of the governor linkage resulted in the maximum no-load speed rise being limited to 30rpm instead of 70 rpm in the earlier engines, thus the maximum attainable crankshaft speed is a little higher than on previous engines. This is illustrated herewith. With the synchronising gear set-up ratio retained at 1 : 1.44 the generator full-load speed was now 1150rpm.
The connecting rod design had been modified to withstand the heavier stresses produced by the increases in b.m.e.p. and speed The small-end bearing had been strengthened by enlarging the gudgeon pin diameter, while the big-end bearing cap and fixing bolts had been redesigned.
The outstanding feature of the intercooler system was that it made use of the main engine cooling water to remove the heat from the charging air, thereby eliminating the need for a separate water circuit with its associate pumps, radiators and piping. The design was such that by passing there whole of the engine circulating water through the intercooler, the temperature rise did not exceed 5 degrees Faranheight.
The electrically-driven cooling-water pump, which was part of the combined pump set, drew water from the radiator and circulated it through the oil heat-exchanger, thence through the two intercoolers in parallel to the engine water jacket and back to the radiator. A thermostatically-controlled radiator by-pass allowed rapid warming-up of the system when starting from cold, and normal running temperature was maintained by two thermostatic switches which controlled the series or parallel operation of the radiator fan motors, allowing them to run at either full speed, half speed, or stopped.
The two intercoolers were fitted directly into wide portions of the inlet manifolds, one to each bank, thus forming an integral part of the engine and causing the minimum of restriction to air flow. They were of the single-flow type, with round tubes and flat spiral fins to give the largest possible heat transfer surface within the space available.
The arrangement of the radiator in the section "Layout of Equipment". They were of the self-draining type and their roof-mounted position allowed a single drain tank to be installed, instead of the more usual pair of tanks and balance pipes.
Another advantage of the roof-mounted position of the radiators - and this applied also to the filters - is that their height above track level rendered them less vulnerable to dirt and contamination, while elimination of large openings in the bodysides simplified the design of the load-carrying bodyside members.
Particulars of the engine are as follows:

Superstructure
The superstructure was designed on the principle whereby the bodysides formed the main load-carrying members so that the weight of the equipment was supported with minimum deflection. The sides were in the form of a "Virendeel" truss being a welded assembly of mild steel plate and pressings with a final skin of 14 gauge steel plate. The unevenness so apparent in rolling stock bodies covered with thin steel plate was avoided by fluting the plate below waist level to give a trim appearance. The bodyside members extended throughout the full length between headstocks, and were insulated by 3 eights of one inch thick sprayed asbestos with a final covering of perforated asbestos board.
T he main bulkheads between the cabs and the engine room were 3inches thick and insulated with fibreglass wool. They were fitted with insulated removable panels to provide access to the control cubicle and the train heating boiler.
The underframe, which acted as a bedplate for the equipment, was an all welded structure. Solebars of "Z" section, formed the bottom part of the bodyside girder, ran the full length of the locomotive, and between these, the boiler crossbars and engine-generator set crossbars were situated. In addition, inner sidebars of rolled-steel channel section and deck-carrying longitudinals of pressed-steel channel section ran between the cross members.
The deck below the power unit was sump-shaped and could be drained. On each side of the deck a trough was provided to accommodate piping and cable runs. Above the main deck, a false floor of chequered aluminium plates provided walkways. These plates were secured by budget locks to facilitate removal for inspection purposes.

Bogies
The bogies were the first examples to be introduced on British Railways of the six-wheeled type incorporating the Alsthem system of twin rubber-cone, body support pivots and radius-arm guided axleboxes. These features were included with the object of obtaining good riding qualities, with a minimum of ribbing surfaces.
The bogie frame was of mild steel fabricated construction, stress relieved after completion of welding. It was supported by four nests of helical coil springs on low-level equalising beams, which were carried from the axleboxes on combined shear and compression rubber pads. The latter assisted in reducing the dead weight on the tracks to a minimum. The helical coil springs were controlled by shock absorbers.
Each axlebox, of the SKF roller-bearing type, was supported by two Silentbloc-bushed radius arms anchored to the bogie frame. This arrangement provided a cushioning effect against fore-and-aft forces, and a degree of lateral resilience which tended to reduce wheel flange wear.
On each bogie the body was carried on two double-ended cone rubber pivots resting in pockets in the bogie and main cross-members. Vertical alignment of the pivots was maintained by transverse stabilising units secured between the pivots and the main frame.
Part of the body weight carried by the bogie was taken by four spring-loaded side bearers, fitted with manganese steel wearing pads, on the bogie frame. Means were provided to adjust the amount of weight carried by the bearers.

Brake Equipment
The break system consisted of a vacuum-controlled locomotive air break operating in conjunction with the vacuum break on the train. In addition, a straight air brake controlled by an independent brake valve, was fitted for use when running light or operating unfitted stock.
All the equipment, which was of Westinghouse design and manufacture, was of the light-weight type in which synthetic rubber valve seats and rubber diaphragm-operated valves were used instead of pistons.
Clasp-type brakes were operated by six externally-mounted 8 inch diameter J.S.L. combined brake cylinders and slack adjusters on each bogie. At 70 lbs per square inch pressure the normal brake force produced was 85% of the locomotive weight. To increase the period between brake block renewals, each block consisted of a fabricated steel head carrying two renewable cast-iron shoes. Ferobestos bushings were fitted to all holes in the brake rigging, while all pins, spigots, etc., were hard chrome plated. Lubrication points on the brake rigging were thus entirely eliminated.
Control of the high-speed running of the exhausters for brake release was effected by contacts in the vacuum brave valve, which closed in the "RELEASE" position. Provision was made for releasing the locomotive brakes independently of the train brakes to facilitate uncoupling the locomotive from a braked train.
To suit the class of train being hauled, two rates of emergency brake applications were provided, the slower rate being used when operating trains of unfitted stock. Selection of the rate required was made by a "Fitted/Unfitted" change-over switch.

Layout of Equipment
In the arrangement of the engine-room equipment, attention had been devoted to the problem of providing a reasonably good degree of accessibility for maintenance purposes, within the severe limits of space imposed.
The radiators for the engine water cooling system were situated at No 1 end of the locomotive and consisted of two panels mounted in the roof immediately above the cantrail. Air was drawn through the radiators by two centrally-placed, vertical, motor-driven fans and discharged upwards through roof-outlets. The radiator panels, ducting, fans, motors, and fabricated supporting framework formed a single compact unit which could be removed as a whole from the locomotive.
Below the radiator unit were located the train heating boiler, air reservoirs, radiator drain tank, and an auxiliary machine group consisting of the air compressor, a traction motor blower, and a combined pump set. In addition, a unit containing certain brake system components, and the engine instruments, were mounted above the auxiliaries.
The central portion of the engine-room was occupied by the engine-generator set, with walkways on each side of it.
At No 2 end of the locomotive, the control cubical was placed against the engine-room No2 cab bulkhead. Between this cubicle and the engine-generator set a second group of auxiliary machines were positioned, consisting of the second traction motor blower and two exhauster sets. Over these auxiliaries a second brake equipment cubicle was mounted and above this, in the roof, was a frame supporting the load regulator and various resister units. The latter were cooled by air drawn in through louvres and extracted by six roof ventilators.
Four tanks containing fuel were located two at each end of the engine room. They were close enough to the bogie centres to prevent alterations to the relative loading of the bogie pivots as fuel was consumed.
The diesel engine exhaust silencer was housed in a removable steel trap above the generators and were suitably insulated.
The water tank for supplying the train heating boiler was slung below the centre of the underframe and was arranged for filling either from a hydrant at platform level or from a water crane discharging into a pull-out hopper on either side of the locomotive near the centre line. To facilitate the use of these hoppers, a maintenance door adjacent to them was arranged so that the top half hinged outwards while the bottom half dropped down and was held in a horizontal position to form a platform for a man to stand on.
The water tank was recessed to allow room for the battery boxes below the underframe. These were provided with hinged tracks forming tracks on which the battery containers could be rolled out of the boxes for maintenance.
Along the curve of the roof above the cantrail a row of hinged louvres were fitted, behind which oil-wetted air filters were secured. The louvres opened upwards allowing the filters to be withdrawn for cleaning. All air entering the engine-room pass through these filters.
Above the engine, a roof trap, fitted with translucent fibre-glass panels, was provided, which, under pneumatic control from a push button, could be unlocked and raised 6 inches to allow hot air to escape from the engine-room before maintenance work was carried out on the engine. An interlock system prevented the trap being raised unless the locomotive was stationary; it also closed the trap, if inadvertently left raised, as soon as an attempt was made to move the locomotive. Provision was made for the trap, when in the raised position, to be slid along the roof to allow removal of pistons and liners.

Cab Arrangement
A full-width cab was located at each end of the superstructure, fitted with large front windows to give a practically unobstructed vision ahead. The glass in these windows was of the gold-film type, electrically heated for demisting purposes. Adjustable tip-up seats for the driver and his assistant were mounted on draught screens. Between these screens and the main bulkhead, inward opening side doors on both sides gave access to the cab.
The arrangement of the driver's controls followed standard practice adopted by British Railways for main line diesel-electric locomotives. In brief, the vacuum and straight air brake valves were on the left of the driver's position, while the master controller was on the right. The latter was equipped with a selector handle - giving "OFF", "REVERSE", "ENGINE ONLY", and "FORWARD" position by the British railways standard master key.
The anti-slip brake valve which could give a 10lb brake application was operated by a push-button located in the end of the power handle.
The driver's instruments were mounted on a panel facing the driving position. In addition to the air and vacuum gauges and the speedometer, an unusual feature was the installation of six edgeways ammeters, one connected to each motor circuit. By this means, the slipping of any pair of wheels could be immediately detected, without the complication of wheel-slip indication relays.
The indicator light system included an "engine stopped" light and a general fault light, the latter serving to indicate the occurrence of any of the following conditions: Low lubricating oil pressure, low water pressure, high water temperature, traction motor blower failure, earth fault and loss of vacuum or compressed air. Indicators for electric and steam train heating were also provided. Illumination of the instrument panels were ultra-violet lights mounted in canopies over the panels.
Other controls comprised push button switches for engine start and stop, exhauster start and stop, train heating on and off, hand locomotive brake cut-out; horn valve; deadman's treadle switch at the driving position and a hand-operated switch at the opposite side.
The locomotive was equipped with a fire alarm system consisting of a series of detectors distributed in the engine-room which operated alarm bells in both cabs. The standard British railways automatic warning system apparatus was also fitted.
A centrally placed hand wheel was provided in each cab to operate the hand brake on the adjacent bogie.
A contemporary styling had been adopted for the cab interior, which was finished in grey and blue with polished timber fascias.