INTRODUCTION

 

The braking system fitted to the Society rolling stock is pneumatically operated, and is a single pipe system, designed to fail safe if the pipe – train pipe – is parted.

 

All pipes are 6mmO/D x 4mm I/D nylon, and all fittings etc. are proprietary items from the Camozzi range.

 

 

BRAKING SYSTEM : HOW IT WORKS

 

 

Each bogie is fitted with a detachable brake assembly plate onto which is assembled 4 brake arms fitted with cycle type brake shoes.

 

An air cylinder is mounted between the arms so that on extending, the arms pivot inwards causing the shoes to come into contact with a disc mounted on each axle, thereby braking the carriage.

 

The cylinder is supplied with air from a compressor mounted on either the locomotive or in a brake truck.

 

Air is fed into the piston end of the cylinder from a pipe which is continuous from the locomotive, or brake truck, to the end of the train – the train pipe.

 

The port on the opposite end of the cylinder is supplied with air from a reservoir, which is supplied with air from the train pipe via a tee fitting and non return valve.

 

When air is admitted to the system, both sides of the cylinder are pressurised.  The cylinder does not extend due to the additional pressure applied by two centralising springs.

 

When air is exhausted from the train pipe, air held captive in the reservoir – by means of the non return valve – causes the cylinder to extend, applying the brakes.

 

The brakes will remain applied until either air is re-introduced into the train pipe, or the reservoir is exhausted by means of operating the exhaust valve – painted RED – mounted on the buffer beam on one end of the carriage.

 

In the unlikely event of a train parting, the train pipe will break causing a loss of pressure in the train pipe, and the brakes will be automatically applied.

 

OPERATION

 

 

ALL TRAINS EXCEPT SOCIETY DIESEL HAULED

 

The system is operated from a control box which is either permanently fitted to the locomotive, or fitted to a umbilical lead plugged into the leading carriage by means of a 7 pin DIN plug.

 

The box is fitted with 3 way, centre off, sprung switch, and 3 LED’s – Red, Yellow, Green.

 

1. Connect the brake truck both electrically and pneumatically to the   

    train.

    IT IS ESSENTIAL TO ENSURE ALL PNUEMATIC CONNECTIONS ARE

    IN THE ANGLED CONNECTOR, AND THAT HOSES “CLICK” HOME.

    ALSO, ENSURE ELECTRICAL LEADS ARE CORRECTLY FITTED -

  KEYWAY AT THE TOP.

 

    DO NOT FIT ANY PNUEMATIC PIPE TO THE RED SOCKET – ONLY

    TO ANGLED DOWN SOCKETS.

 

2. Connect either the umbilical lead to the first carriage, or connect

    a standard connecting lead between the 7 pin plug on the

    locomotive, and the 7 pin plug on the leading carriage.

 

3. Switch on brake truck – switch with RED Led in lever.

    Compressor will start.

    Wait until compressor cuts out.

    LED on locomotive control box will show RED.

 

4. Push brake operating switch on loco control box to “OFF” and

    hold for 5 seconds. GREEN Led will light.

 

5. Push brake operating switch on loco control box to “ON” and

    hold for 5 seconds. RED Led will light.

 

6. Repeat 4. Check brakes are released.

 

7. Repeat 5. Check brakes are on.

 

The system is now ready for use.

 

NB. IT IS ESSENTIAL TO HOLD THE SWITCH IN EITHER THE “ON” OR “OFF” POSITION FOR A FEW SECONDS TO ALLOW ALL AIR TO EITHER ENTER OR EXIT THE SYSTEM.

 

It is recommended that the brakes be applied at all times when the train is in the station, and loading and unloading.

 

The guard should depress the Emergency Stop switch in the event of an accident or emergency, but also should do so when loading in the station. This will prevent the driver releasing the brakes until such time as the guard is happy that the passengers are safely seated and ready to go, at which time the guard should release the Emergency Stop button, allowing the driver to release the brakes.

 

** Locomotives fitted with their own compressor and controller need only connect pneumatically to the train, the control valve on the locomotive admitting and exhausting air as required.

Brake truck No: BT1 is the only brake truck that can be used in this instance as it is the only brake truck with the facility to switch off the compressor.

 

This is accomplished by switching the toggle switch with the BLUE Led to the “OFF” position – i.e. Led not lit.

 

UNDER NO CIRCUMSTANCES SHOULD ANY OTHER BRAKE TRUCK BE USED UNLESS IT IS ONLY TO BE USED FOR THE GUARD FACILITY, IT WHICH CASE THE BRAKE TRUCK SHOULD BE SWITCHED OFF.

 

Trains of 2 or more coaches will take progressively longer for the brakes to operate, therefore the control switch should be held in the “ON” or “OFF” position for a suitable time.

 

Drivers can, however, achieve partial brake application by ‘flicking’ the switch lever, thereby exhausting a small amount of air at any one time.

 

The Yellow Led will give an indication of partial brake application.

 

Also, if the Yellow Led lights up when the control lever has not been operated, this will be an indication of an air leak, causing the brakes to either start to release, or apply.

 

If this happens when running, push the control lever to the “OFF” position until the GREEN lights.

 

Investigate leak on return to the station.

 

 

DISPERSAL

 

 

When the stock is no longer required:-

 

1. Remove electrical connection from locomotive.

 

2. Break train where required by removing both electrical and

    pneumatic connections BEFORE disconnecting the carriage

    coupling.

 

3. Using one of the pneumatic pipes, push one end into the RED

    pneumatic socket located on the buffer beam at one end of

    each carriage

 

4. Repeat 3 for each carriage and brake truck.

 

 

THE BRAKE TRUCK

 

The brake truck contains all the pneumatic and electrical equipment to operate the braking system.

 

A 12 volt battery is connected via a double pole switch – RED Led – via a 20 amp fuse and relay to a 12 volt compressor which supplies air into and underslung centrally mounted receiver.

 

Air is distributed from the receiver to:-

 

a) A pressure switch which switches the compressor on/off at a

    predetermined pressure – 75/80psi.

 

b) An exhaust valve, to exhaust the receiver, located on the rear

    buffer beam, painted RED.

 

c) A pressure gauge.

 

d) Main control panel.

 

Air is fed, via a pressure regulator, set at approx. 60 psi, via a non return valve into a solenoid valve which feeds air into the train pipe, which in turn feeds air into the piston end of the brake cylinder, and through a non return valve into the brake cylinder reservoir.

 

The brake cylinder reservoir is mounted on the upper side of the chassis, and has feeds to the rear end of the brake cylinder, and also to the exhaust valve on the rear buffer beam.

 

Air is also fed into a small cylinder which acts as a system status indicator.  The cylinder is fitted with a diablo roller which makes contact with limit switches as it extends and retracts.

 

In fully retracted mode, with no pressure in the train pipe, the RED Led is lit. The centre switch operates a YELLOW Led, whilst on full extension, with the train pipe fully pressurised, the GREEN Led is lit.

 

When the driver operates the control lever to “OFF” position, the inlet solenoid valve opens, admitting air into the system, retracting the brake cylinders, and extending the small indicator cylinder thereby lighting the GREEN Led.

 

On operating the brake switch lever to “ON”, the outlet solenoid valve is actuated, exhausting air from the system, causing the brake cylinders to extend by virtue of the captive air in the brake cylinder reservoirs, and the small indicator cylinder retracts, lighting the RED Led.

 

The Emergency Stop switch is wired through a solenoid so that when depressed, the outlet solenoid valve is energised, exhausting the system, and applying the brakes.

 

A red flashing Led is mounted at the rear of the truck as a rear light, and red Led’s are fitted around the Emergency Stop button so that it can easily be located in the dark.

 

These are energised by switching on the toggle switch with the green Led.

 

All electrics are protected by fuses:  Compressor - 20 amp

 

                                                              Control circuit – 5 amp

 

Fuses are automotive spade type colour coded.

 

In addition, BT1 has a BLUE Led toggle switch which isolates the compressor, whilst leaving all other functions intact.

 

Also fitted to the control panel is a 3 pin battery charging plug and battery condition indicator.

 

The battery condition indicator is illuminated at all times, even when the truck is switched off, and charging of the trucks should take place as soon as possible after the yellow light is lit.

 

ALL BATTERIES SHOULD BE KEPT FULLY CHARGED.

 

 

 

TROUBLESHOOTING

 

 

1.  My locomotive is connected electrically, or I have fitted the        

     umbilical chord, but the brakes do not work.

 

    Check if any Led’s on the control box work when you operate the

    brake lever. If not:

 

   i)     Umbilical chord or cable incorrectly fitted.

 

  ii)    Brake truck not switched on.

 

 iii)   Connecting leads between carriages not correctly fitted, or

        faulty.  Connect umbilical chord to brake truck and verify

       correct operation. Then connect each carriage in turn and

       check.

 

2.  The red Led lights, but brakes do not operate.

 

     i) Check air pies correctly fitted to angled fittings.

 

   ii) Uncouple air pipe from carriage leaving other end attached to

       the brake truck. Check if compressor runs.

      If not, check compressor fuse.

 

 iii)  Emergency red button been operated  on brake truck. (Twist to release)

 

3.  The brakes seem to drag.

 

     Push operating switch lever to “OFF” position. Check for free

     running.  If compressor runs after a few minutes, repeat above

    but for each individual carriage, as the cause will be an air leak.

 

4.  I apply the brakes, but they seem to ‘bleed’ off.

 

     Air leak from brake cylinder reservoir.  Check all fittings etc.

    If problem is not found to be a joint or worn pipe etc. remove the

    non return valve, dis-assemble, clean rubber membrane and re-

    assemble.

 

In the event of a brake failure, visually check all pipes and fittings for damage, and listen for air escaping.

 

If there are no immediate signs of the problem, and 1 – 4 have been checked, or are not applicable, brush all fittings with a 50/50 mix washing up liquid and water.  Look for bubbles.

 

In any event:

 

1. Record the apparent problem on the relevant Carriage/Truck record card.

 

2. Take the carriage/truck out of service

 

3. Place ‘DO NOT USE’ label on carriage/truck.

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