Push Gathers Steam to Restore a Historic Loco
J515 Updates from the Seymour Railway Heritage Centre
Rare Arnott's biscuit van restored
In recent weeks there have been a few train operations, a couple of equipment challenges and more track work undertaken.
We will start with one of the problems and move on chronologically.
Generally speaking the underside of one carriage is similar to another. But some cars are a bit different. Three of the fleet have underfloor diesel alternators to provide power for air conditioning, lighting and catering. During the running of a charter to Melbourne the diesel alternator under 3BS refused to operate as intended.
The fuel tank was diagnosed with contamination and so removed from the car for flushing and cleaning. With the tank refitted Frank and Robbie are reconnecting the pipes ready for testing.
The reason for the early attendance was for our train to Bacchus Marsh and the Strawberry Festival on Saturday 17th November. Hauled by X31 and B74 the train is leaving the loco depot heading up to the station to pick up passengers and be on its way.
So what is this?
This is a supply contactor for the head end power supply which has been removed from P22. Following the first standard gauge charter a month or two ago, there were issues with both head end power and ground faults on both locomotives.
The head end power issues seem to be related to this contactor and its twin. The contact bridges have been removed to allow the carriers to be freed up. It seems that moisture has been getting into the compartment where this equipment is housed for quite a while.
Both the contactors and housing have been attended to and now we will see how things perform.
One clear and mild morning the machinery is gathering by T357.
The ground faults mentioned above with respect to the standard gauge locomotives have been investigated and actions determined. As for P22, the main generator has received some attention but with 357 the problem is the electrical resistance of the armature in number 2 traction motor. Depending on just what the details of the fault are, it can sometimes be repaired in situ.
A little while later the local crane man and his machine are on site and we have set up and are lifting T357.
The armature fault is not one of those that can be dealt with in position. The only option is bogie out, motor out, new motor in, bogie back in.
There are a couple of option available when thinking on how to extract a bogie. Where access is suitable the job can be done with one crane by lifting one end of the loco high enough to roll the bogie out. This is cheaper and simpler than the more complicated option of lifting both end of the loco at the same time.
So with one end up fairly high we are waiting for something. Maybe it is for the photographer to get his picture and get back to work.
A close look shows the loco to be high enough for the bogie to come out.
Once the bogie is rolled out the next move is to lower the loco down to its usual height. To the right a couple of quarter sleepers lie ready to put on top of the rails so that the weight of the loco can be supported on the cowcatcher.
At the other end of the loco there has to be some suitable packing so that as the loco is lifted and the weight comes of the bogie at this end, the cowcatcher can support the weight of the loco.
With the other end hanging on the crane it is vital that this end is stable and the weight is evenly distributed.
A T class loco weighs around 68 tonnes. About 28 tonnes is in the two bogies leaving 40 tonnes in the body. Therefore the crane has to lift 20 tones and the remaining 20 tonnes in taken on the cowcatcher and then via the packing to the ground.
At the other end we are down and sitting on wood packing. The nylon slings used to connect to the shank of the auto coupler are lying aside to allow the crane to be used to lift the traction motors in and out. There is thick rubber pads around the coupler shank and timber packing each side of the coupler so it does not swing.
Whilst is is possible to lift a loco from lifting points on the side of the body, special lifting attachments are needed along with a spreader bar. If suitable packing can be used at the other end under the cowcatcher, lifting from the coupler is a sound and simpler process.
T class locos are fitted with D29 type traction motors which weigh around 2.3 tonnes or so. This is the new one which is from our stocks of rebuilt bits and pieces. The pinion gear on the end of the armature will engage with the 'bull' gear on the axle to drive the loco along.
Under the top cover this is the commutator part of the armature. At the bottom is one of the four brush boxes which in this type of motor have two brushes side by side. The rectangular aperture at the top is the cooling air duct that receives air blown from the traction motor cooling blowers.
By referring back to the second previous picture you should be able to see how the suspension bearing caps fit to a motor. these are the caps from the motor being removed and the bronze, white metal lines bearing shells are in the foreground. After cleaning it was found that the bearing shells were well fit for reuse with the new motor.
This is the view looking into the old motor. It is nowhere as clean as the new one and the reality is this is the cause of the fault.
Traction motors operate on DC current up to around 350 volts at hundreds of amps of current. If the insulation is poor, current leaks from where it should be in the windings to the frame (or ground) of the motor. This causes significant electrical damage and in some cases will result in a locomotive having a major electrical fire that can be catastrophic. An electrical circuit commonly referred to as the 'ground relay' detects leakage and shuts of the power from the generator. Whist this prevents damage, it stops the loco from being able to power.
This motor has low resistance from the commutator to ground which is probably caused by a combination of dirt (we tried cleaning ) and less that perfect insulation.
Lunch is over and it now time to get back to it. The suspension bearing surfaces of the axle have been cleaned and inspected and all found to be good. The 'bull' gear is prominent in this view and its diameter shows that a gear ratio of around 4;1 exists between motor and wheels.
The new motor is being lowered into position on the axle watched or is it guided by James and Quentin. Before this the axle and bearing shells were thoroughly oiled. There is nothing like pre lubing to make sure oil gets to where it should and that problems are eliminated in the reassembly process.
The motor is suspended from a single chain on the rear lifting lug. This makes it hang forward and allows the bearing shells to be engage the axle. When correctly seated on the axle, the crane will lower the motor which will then pivot on the axle and the rear will descend to the limiting lugs against the bogie cross member.
After the motor was lowered the bearing caps were refitted, the gear case assembled over the pinion and bull gear, the nose suspension spring pack inserted and the loco lifted and bogie refitted.
With the bogie back under the loco, the traction motor cables and brakes were reconnected and the loco run up and down for a test;. hey presto, all is good!
A couple of days later the real test came with P22 and T357 off to Melbourne and Albury. All was well.
The following week it was time for track. Outside the gate in Vline territory their inspection revealed it was time for some re-sleepering works. As we no longer need the broad gauge portion of the former dual gauge back gate access, first task was to get rid of the unused rail.
The end of day view, actually the next morning as revealed by the shadow, there are no rails left. From the photographers feet a new connection will be made to the new turnout in the left hand track under the last car in view.
The keen eye will notice that the standard gauge train has been stabled differently. This time following the outing all three cars are together with P22 so that ongoing annoying head end power issues can be fully diagnosed and resolved.
In the shed - Robbie has been doing various things but now he is back on to P23. All the body side removable panels and doors are laid out for cleaning, repairs and painting. Some are better than others while a few requiring quite a bit of work.
Plans for ongoing gauge conversion calls for another two AS Commonwealth bogies to be made ready for early next year. Two bogies are in the process of stripping. Broad gauge wheels will be put aside and standard gauge brake rigging restored followed by replacement standard gauge wheel sets being fitted.
This is the first bogie now in bits with the broad gauge wheels aside. They will go into stock and see use in another vehicle next year.
The new connection to 14 track will be connected mid next week followed by a start on new standard gauge tracks 15 and 16 and conversion of 20 track.
This article first appeared on srhcblog.blogspot.com
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