ENGINE
The engine is a 145 litre Mirrlees Blackstone 8MB275T (8 cylinder ~ Mirlees Blackstone ~
275 mm cylinder diameter ~ Traction) diesel engine. It has been designed for easy access
and rigidity of components together with compatible stress levels. High cylinder pressures
ensure low fuel consumption. The engine is an 8 cylinder in line engine producing 3100 HP
at 1000 RPM. it is turbo - charged and has intercooling. The cylinders are numbered
opposite to the normal method used, i.e., No8 cylinder is the first when looking at the
free end of the engine. The firing order is 1,3,2,5,8,6,7,4. A Woodward governor is used
to control the fuel racks, this governor is in turn controlled by the micro processor.
Should the engine exceed 1100 RPM the engine overspeed trip will operate to disengage the
fuel injector pumps from the camshaft so starving the engine of fuel thus shutting it down
before any damage can occur. Because the engine drives alternators, to start the engine
two starter motors are provided. Should the starter motors become overheated a thermal
protection device will prevent them from re - engaging with the starter ring until the
temperature has reduced.
ELECTRICAL SYSTEMS
The diesel engine on The class 60 locomotive drives :-
a. Main Alternator.
b. An Auxiliary Alternator.
The Main alternator:-
The sole purpose of the main alternator is to provide electricity for the traction motors
for which it will supply up to 6,800 amps. As an alternator produces AC current and the
traction motors use DC current a rectifier has to be used. This rectifier is mounted in
the clean air compartment at No2 end of the locomotive.
The Auxiliary Alternator.
This is coupled to the main alternator and is driven in the same way. It provides power
for the locomotive auxiliary machines, battery charging and for the field current for the
traction motors.
The main machines driven are:-
1) Radiator Fans (x2) ~ To Cool the Coolant !
2) Engine crank case vent motor ~ To take waste heat & pressure out of the crank case.
3) Lubricating Oil priming pump ~ Pumps Oil around the engine to get 1.35 bar of pressure
in the system so that the starting sequence can commence.
4) Fuel Oil pump ~ Pumps fuel to the fuel rack on the engine (if it fails whilst the
engine is running it might keep running at very low revs with fuel gravity fed).
5) Traction Motor Blowers (x2) ~ These keep the motors Cool and Clean. But if one was to
fail it would knock out all 3 motors on that bogie.
6) Filter Dump Pump ~ Blows all the s#%t out of the Large Air Filter on the side of the
Clean Air Compartment.
7) Compressors (x2) ~ Make all the Air.
8) Cab Heaters (x2) ~ Provide an Ambient environment in the cab.
THE CONTROL PANEL
The auxiliary equipment is protected against excessive over current or low current. This
protection is either by fuse, circuit breaker or in some cases a relay. This equipment is
mounted on a control panel in the clean air compartment of the locomotive.
Fuses:
On modern locos most electrical equipment is now fused by Circuit Breakers though the
following are still fuses (which come in 2, 20 & 25 amp varieties):-
Lighting fuses (x2) ~ Scavenger pump fuse ~ Phase reference fuses (x5)
Battery Charge ammeter:
This is mounted top left hand of the panel and shows that the battery is being charged
when the engine is running.
Circuit Breakers: All the following electrical equipment is protected by C.B's (which rate
from 20 - 100 amp):
DC Equipment:-
Control Circuit ~ Brake Circuit ~ A.W.S. Circuit ~ Parking Brake Circuit ~ Electronics
Circuit ~ Health Monitor Circuit ~ Fuel Pump ~ Lubricating Oil Pump ~ Air Dryer/Screen
Heat ~ Hot Plate ~ Cab Heater (x2) ~ Lighting Circuits (x2) ~ Start Circuits ~
Communication Circuits ~ Fire Circuits ~ DC Supply.
AC Equipment:-
Compressor Circuits (x2) ~ Radiator Fan Circuits (x2) ~ Traction Motor Blower Circuits
(x2).
Also Mounted on the panel are the following :-
Traction Motor Isolating switch ~ which allows the driver to knock out ONE traction motor
due to the fact that sometimes if a motor becomes defective the chances are the current
will be cut to the others and isolating it altogether will overcome this.
DSD Isolating switch & AWS Isolating Switch ~ If either the DSD or AWS Becomes
defective it is designed to "Fail Safe" i.e apply the brakes and these are
"get out of trouble" switches which allow you to clear the main lines and fail
somewhere more convenient.
Engine maintenance switch ~ Cuts the output from the alternator to the traction motors and
allows maintenance staff to work on the engine without fear of dozy drivers moving it!
Control Cut Out Switch ~ This switch allows a dead 60 to control a 60 that works (if the
jumper is in).
Diagnostic Test Button ~ Press this to check all the LED's on the Diagnostic panel are
working.
Reset Button ~ Press this to Reset any fault indications on the Diagnostic panel that may
be giving you trouble.
Fuel Pump Test Button ~ Self explanatory.
Diagnostic Panel ~ Whilst this panel is basically for maintenance purposes, it is a useful
aid to the driver. in the event of a fault, the appropriate indicator lights, and even
though the fault may have been cleared, it remains lit for maintenance purposes. The fault
indications may be cleared by maintenance staff only If a fault is of a type that may be
reset by a driver, flashing indications are used. The indicator flashes until the fault is
cleared or, where appropriate, the reset button is pressed. The indication then changes to
a continuous red light, Re - occurrence of the fault causes the indicator to flash again.
The green micro healthy light is lit under normal conditions. if the lamp is not lit, all
diagnostic panel indications are to be disregarded. The panel is mounted in the control
cubicle where it is clearly visible to the driver. A test button is provided so that the
operation of all the lamps may be checked. The diagnostic panel gives an indication to
crew of a fault or event as shown over.
COOLING WATER SYSTEM
The system is a closed type employing high rates of coolant flow to ensure low temperature
throughout the engine water jacket, cylinder liners and cylinder head. The self contained
cooler group has two AC fan motors to control the temperature. The pressure within the
system is controlled by a pressure\anti - vacuum valve, and circulation is by a
mechanically driven pump on the free end of the engine. High temperature and low level
indications are provided.
Circuit Description:
The coolant water is drawn from the cooler group by the engine driven pump and passed to
the lubricating oil heat exchanger which is mounted on the engine "A" bank, from
there it flows to the charge air cooler, the cooler has a central dividing plate, the
water enters the cooler at the bottom of one side, flows up over the plate and down the
other side. A bleed on the top allows a small amount of water to return to the header tank
and prevents any build up of air within the cooler. On leaving the charge air cooler the
water splits into two, one goes to the turbocharger and then directly back to the cooler
group, this is restricted by the size of the outlet pipe. The other forms the main circuit
and splits into eight branches of the coolant manifold. The manifold distributes coolant
to each cylinder, coolant passes round the liner barrel then via the cylinder collar to
the cylinder. From the cylinder head the coolant flows via the outlet manifold to the
cooler group. A further vent pipe comes from the coolant manifold to bleed water to the
header tank and again ensure no air builds up within the system.
The Cooler Group:
The group is connected to the engine by flexible hoses. The unit contains radiator
elements, header tank, pressure relief/anti vacuum valve, filler valve, contents gauge,
low water level switch, 2x three phase AC induction fan motors and radiator shutters. No
thermostatic valve is provided in the coolant system.
Radiator Elements:
These are mounted in the roof. Radiator louvers are fitted on the upper side of the
elements and are hinged on one edge, with a rubber inset on the other. The louvers overlap
slightly so the seals prevent the ingress of coal dust and fly ash when the fans are not
running. Further protection to prevent damage by heavier objects is given by a screen and
wire mesh. Air is drawn in through the locomotive side and forced out of the roof louvers
via the radiator elements.
Radiator Fans:
The fan motors are controlled by individual thermal switches. The switches are mounted on
the outlet manifold between the engine and the cooler group. Thermal Switch No 1 closes at
72C to run No 1 fan and opens at 65C to stop it. Thermal Switch No 2 closes at 80C to run
No 2 fan and opens at 75C to stop it.
Pressure\Level control:
A pressure relief valve\anti vacuum valve is fitted to the cooler group header tank to
prevent excessive pressure in the system. A low coolant level switch is also incorporated
in the header tank, if the level falls below a predetermined level, the level relay de -
energises the engine run valve and the lubricating oil priming pump contactor, this shuts
down the engine and prevents it from being restarted until the coolant level is restored.
A coolant level indication is given on the control cubicle and a general alarm light on
the drivers desk. Filler connections are provided on both sides of the locomotive.
High Water Temperature: High water temperature is sensed by a thermal switch in the
coolant outlet manifold. If water temperature reaches 85C an indication on the control
cubicle is given along with a general fault light on the drivers desk. The diesel engine
is returned to idling speed, when the temperature falls to 78C power will be available.
Coolant System Data:-
Coolant System Pressure Relief valve: 0.4 Bar.
Flow Rate at 1000 RPM: 1.75 -2.5 BAR.
Radiator Fan motor: 30 KW @ 1,320 RPM.
Coolant Flow Rate: 84 C/Mtrs/Hr at 1000 RPM.
Air Flow: 52 C/Mtrs/Sec.
Radiator Thermal Switch Nol: Closes 72C Opens 65C.
Radiator Thermal Switch No2: Closes 80C Opens 75C.
High Water Temperature Switch: Closes 85C Opens 78C.
LUBRICATING OIL SYSTEM
The system is a full flow type with course and fine filtration, pressure regulation,
temperature control and low oil shut down features. A priming pump is provided to
circulate oil prior to engine start, and there after an engine driven pump takes over.
System description:-
Oil is drawn from the sump via a course filter to the oil pump, on leaving the pump oil
flows to the pressure relief valve which protects the thermostatic valve, heat exchanger
and filter against excessive pressure on cold starts. Oil in excess of 7 bar returns to
the sump. After the pressure relief valve, oil depending on temperature, passes, through
the heat exchanger or by - passes it, to the filter. The filter is a full flow type, with
a filter blocked/restricted visual indicator. Oil passes from the filter to the regulating
valve which limits the pressure in the main gallery to 4.2 bar, excess oil being returned
to the sump. the oil passes round the engine via internally drilled ports and returns to
the sump from a hole in the centre of the underside of the piston. Oil is supplied to the
overspeed trip governor, turbo charger and engine governor. At the engine governor it does
two things, firstly it lubricates the governor drive shaft, and secondly supplies a
pressure indication to the low lubricating oil pressure shut down, in the case of low
pressure this returns the governor to a no fuel position causing the engine to shut down.
Protection:
On this locomotive, shut down is via either the running oil pressure switch or the engine
governor. In both cases the engine will stop when oil pressure falls to 1 bar (Normal
pressure will be approx 4.2 bar). The governor will sense falling pressure and reduce
engine speed (below 3.1 bar) towards idle (1.38 bar), and at 1 bar pressure will after 20
seconds delay return the fuel rack back to the no fuel / shut down position.
The priming system:
An electrically driven priming pump draws oil from the sump via a course strainer and then
via the same route as above. A non return valve is fitted on the output side of the
priming pump to keep the system primed and protect the priming pump against excessive
pressure. the priming pump runs for 30 seconds prior to the engine start sequence.
Crank case extraction and recuperator:
Ventilation of the crankcase is by DC electric motor and fan, oil is separated out and
returns by gravity to the sump. The air/gasses are discharged out of the engine roof.
FUEL SYSTEM
The system is similar to those used on other diesel electric locomotives. A single tank,
underslung, having a contents gauge, mechanical float and filler mounted on the side. the
fuel system is a full flow type with the rate of flow being three times the amount
required at maximum load. the return fuel line is also pressurised and excess fuel being
returned to the suction side of the transfer pump.
Circuit description (low pressure):
Fuel is drawn from the tank via a suction strainer by a motor driven transfer pump, it is
then delivered from the pump to a pressure relief valve any fuel in excess of 2.4 bar is
returned to the suction side of the pump. Fuel from the pressure relief valve passes
through a fine filter to the supply manifold and then to the injector pumps. The injector
pumps have fuel flowing through them at ail times the pump is running. The return manifold
being pressurised at 1.7 bar, any fuel in excess of this pressure being returned to the
suction side of the transfer pump. Because this manifold has a pressure within it, shock
waves and turbulence at the injectors is prevented.
Circuit description (high pressure):
Each cylinder has its own fuel injector pump and injector. Fuel from the injector pump is
passed to the injectors at 5,570 psi. any excess fuel flows to the return manifold. The
fuel injectors are similar to others used except they are very long (700 mm) 28 inch.
Fuel System data:-
Low pressure flow: 1660 litres per hour.
Max High pressure: 17, 200 psi (1170 bar).
Engine Governor:
A Woodward Governor is fitted at the alternator end of the engine, this governor controls
the fuel rack and thus engine speed.
Idle speed of 400 rpm.
Max speed of 1000 rpm.
The engine speed is in 8 steps, but as drivers power controller is notchless variable
power can be selected. The governor has protection devices for low lub oil, charge air
failure and excessive fuel, incorporated within it. An externally fitted engine run valve
performs the normal functions of stopping and running the engine. As the driver opens the
power controller towards maximum a variable differential transducer inputs signals to the
microprocessor which then determines the engine rpm and alternator excitation to match the
demanded power. By increasing and decreasing excitation in step with the diesel engine a
stepless increase in power can be obtained. Engine rpm is controlled by four solenoids
within the governor.
Overspeed Trip:
Should the engine governor fail to prevent the engine rpm from exceeding 1100 the
overspeed trip will operate and cause a cam under the fuel injectors to operate and
disengage the pumps from the camshaft, the engine stops with no fuel.
Engine charge air and Exhaust system:
The engine is basically the same as any other locomotive but more attention is given to
air cleaning, exhaust noise levels and the use of a single unit high performance
turbocharger.
System description:
Air enters the locomotive via primary centrifugal filters located in the body side, and
passes into the clean air compartment. Combustion air is taken from the clean air
compartment to the secondary filter box then by ducting to the turbocharger. Compressed
combustion air is passed through the intercooler to the air manifold and the cylinder
heads. Exhaust gasses pass from the cylinders via the outlet manifold to the turbocharger
and then out to atmosphere (if either or both the internal doors between the Hot Engine
Room and the not so Hot Radiator compt are not shut you can loose up to a third of the
loco's power !).
Air Filters:
The primary filters are self cleaning, a motor driven dump fan discharges the dirt from
the bottom of the locomotive and on to the track.
Silencer:
To meet stricter noise emission levels the silencer is a larger unit than normal, it is
mounted on the roof of the clean air compartment and is so designed to follow the roof
curvature line.
Data:-
Turbocharger rpm: 23,400.
Charge air pressure: 2.37 bar.
THE MAIN AIR SYSTEM
The class 60 is designed by Westinghouse. The air system can be divided into three
different working pressures:-
1) Main Air - 10 Bar.
2) Main Reservoir supply and pipe - 7 Bar.
3) Air Brake pipe - 5 Bar.
(1 Bar = 14.5 psi).
System Description:
The locomotive has two 3 phase AC compressors, each compressor is fitted with an air
aftercooler. Air is drawn into each compressor through its associated air intake filter
and flexible hose, and is then delivered into the main reservoir via a flexible hose and
check valve. The check valve prevents a loss of air in the event of a burst delivery hose
or a failed compressor. The compressor is governed in the normal way (even though it is an
AC machine ). The governor pressures are :8.5 Bar to start the compressors. 10 Bar to stop
the compressors. In the event of a governor failure it can be isolated by operating the
governor isolating cock. The system will then be regulated at 12 bar by a safety valve. A
Metcalf/Salam air dryer, located in the main reservoir air line, ensures that only dry air
reaches all air operated equipment by removing moisture from the compressed air supply.
The system has three main air reservoirs giving a total capacity of 1000 litres. Each
reservoir is fitted with an automatic drain and a manually operated drain cock. Further
air filtration takes place before the air enters the main reservoirs. A low main air
governor is fitted to the system to remove traction power and apply the brakes should the
pressure fall to 4.5 bar. This governor also ensures that the locomotive becomes
inoperative until the main air system has been charged sufficiently to ensure satisfactory
operation of the brakes. Two brake supply reservoirs, one for each bogie, are fed via a
strainer, check valve and choke valve. The brake supply reservoirs can also be supplied
with air at 5 bar from the brake pipe via a similar strainer, check valve and choke valve.
The brake supply reservoirs feed the distributors, each distributor having connections to
:-
1) A control reservoir fitted with a release valve.
2) The brake pipe.
3) A brake selector cock giving Goods/Passenger timings.
4) The brake cylinders via isolating cocks, flexible hoses and double check valves.
An air supply of 10 bar is also taken to the automatic air brake controller, the
locomotive main reservoir pipe, and to each straight air brake controller for operation of
the straight air brakes. The cab gauges are led to give an indication of the main
reservoir pipe pressure.
Metcalf - Salem "Twin Tower" Air Dryer:
The dryer has been developed especially to suit traction requirements. The dryer removes
moisture from the compressed air supply and ensures that only clean, dry air reaches all
air operated equipment. This ensures that all air operated equipment functions more
efficiently. The twin tower system includes coalescers desiccants. The coalescars remove
impurities from the compressed air supply, and the desiccants, which are a type of
molecular sieve and are located in the air dryer canisters, remove the moisture. After
removing the moisture the desiccants are regenerated (restored to their original dryness)
during the operating cycle. The two air dryers are connected by a common inlet manifold
with integral pre - colescer, and a common outlet manifold. Also included is a memory type
electronic timer which controls the system cycle and allows the unit to regenerate only
when a pre - determined pressure (6.7 bar) is reached and the compressor is operating.
Until such time both dryers allow a maximum flow of air to pass and charge the entire
system. Air enters the inlet manifold and flows into the pre - coalescer where it passes
through the coalescer element, this removes microscopic oil aerosols, a desiccant in the
air drier then removes water vapour from the compressed air. With the compressor pumping
and the pre - determined pressure reached, the R.H side of the dryer begins to regenerate
while the solenoid valve is energised allowing air to pass and to close the inlet check
valve, at the same time the spring loaded outlet check valve closes, when both the inlet
and outlet check valves are closed and the air dryer is isolated, the sump mounted purge
valve opens and there is a sudden drop in air pressure, the drop in pressure forces the
collected impurities from the air dryer to atmosphere whilst the moisture absorbed by the
desiccant beads is released to the surface of the beads, the moisture released to the
surface of the beads is picked up by the dry air and exhausted through the open purge
valve at a level slightly above atmospheric pressure, at the same time any collected
impurities are exhausted from the pre - coalescar to atmosphere. While the R H side is in
the regenerating phase the L H side is in the dehydrating phase, This reverses every 60
seconds.
Main Reservoir Supply and Pipe (7.0 bar system):
The main reservoir pipe is coupled between locomotives coupled in multiple and between all
vehicles in the train working on the two pipe system. The system is fed from the 10 bar
main air supply via a combined filter/regulator, (which reduces the pressure to 7 bar) and
a duplex check valve ( to prevent main air falling below 5 bar should the reservoir pipe
rupture). The main reservoir pipe feeds a pressure gauge in each cab, also the brake pipe
pressure control unit, the sanding valves and the warning horns.
The Air Brake System (5 Bar System):
The automatic air brake on the locomotive is the traditional type, where the pressure is
varied in the brake pipe. The pipe being continuous throughout the train is charged to 5
bar to release the brake and reduced accordingly to apply the brake. Each vehicle is
fitted with a distributor which responds to the pressure in the brake pipe to apply or
release the brake. On the locomotive each distributor (of which there is one for each
bogie) is connected to:-
1) A control reservoir fitted with a release valve.
2) The brake pipe.
3) A brake selector cock giving Goods / Passenger brake release timings.
4) The brake cylinders via an isolating cock, flexible hose and double check valve.
The brake pipe pressure can be directly vented from the cabs by operation of the drivers
emergency valve. A switch is included in the valve which is connected to the electrical
control circuits, and to the brake control unit which also vents air train pipe when de-
energised. To reset the emergency valve the knob requires pulling fully out. An interlock
valve arrangement is provided between the parking brake and the automatic air brake which
comprises of:-
1. An emergency application valve.
2. A vent valve.
3. An interlock magnetic valve.
If an attempt is made to move the locomotive with the parking brake applied, air train
pipe pressure is automatically vented when the locomotive speed reaches 6 mph, thus
applying the brakes.
The Straight Air Brake:
The straight air brake provides a means of applying and releasing the locomotive air brake
independently of the train brake. A straight air brake valve is provided in each cab for
the control of this brake. Each valve has a control handle with three dented operating
pistons corresponding to APPLY and RELEASE and an unmarked VERTICAL position. The inlet
port of each valve is coupled to the 10 bar air system and the outlet port is coupled via
a double check valve to a common delivery pipe which then branches into two, to the
individual brake cylinders, via a protection choke, pressure regulator and an isolating
cock. The brake is applied by moving the brake valve forward to the APPLY position, this
allows air to flow from the 10 bar supply to the brake cylinders, when the required brake
cylinder pressure is reached the handle is moved to the VERTICAL position cutting of the
supply. If required, the brake valve can be left in the APPLY position, the brake cylinder
pressure being limited to 4.25 bar. Similarly the brake cylinder pressure can be released
by moving the brake valve handle backwards to the RELEASE position, this releases the air
from the brake cylinders to atmosphere, when the brake cylinder pressure has been reduced
to the required level the brake handle is moved back to the VERTICAL position preventing
any further loss of pressure. In running it is essential that the brake valve in the rear
cab is in the RELEASE position.
TRACTION MOTORS
The six traction motors are axle hung, nose suspended on rubber bushes. Each motor drives
an axle through a single stage sup reduction gear. The traction motors used are of the
SEPEX type, ie the armature coil and the field coil are separately supplied with
electricity, because of this each motor can be controlled independently thus if wheelslip
occurs on No 1 motor then the load to that motor can be reduced until the wheelslip ceases
without reducing the load to the other 5 motors. The traction motors are all monitored by
the inboard computer. Each bogie is restrained to the body by four wire slings. Sand boxes
are attached to each bogie corner and the sand is ejected to the outer wheels by air.