Getting power to flow through 488 again

Dateline: 12th May 2015

Early last year, with the side panels removed from the lower saloon of 488, I started investigations into how to strip out the antique wiring. A dizzying array of assorted wires had been used for different purposes in the car, and so my initial investigations required some patience, to identify the purpose of each cable.

It became clear that during the car's refit in around 1929, many wires were merely chopped off and left in the chassis, and the replacement wires fed in alongside them. My feelings were that the unending nature of the series wiring being woven through the bodywork 'had to be seen to be believed' - and yet, it all 'made sense', because it would have worked! In addition, I found that the original routing of the lighting wiring was unnecessarily complex - and yet, it told the story of people wiring items because 'they had always wired them that way'. From an historical point of interest, the old wiring gave away the clue that it had been made 'pre-formed'; the original high current traction wiring consisted of rigid seven strand cable, and this being very hard to bend, at the time the car was being constructed in 1903, the wiring would not have been threaded through the body, but would have been installed into the structure of the saloon in the form of a pre-shaped harness.

Upon locating the traction wiring [multi-strand, heavy duty cabling], I found that inevitably its paper and cloth insulation has long since degraded such that it would no longer be effective. Due to the confined space, it was not an easy task to extract all of this, and any attempt I made to bend one of the cables resulted in all of the crisp insulation breaking off, not surprising as these cables were probably of 1903 vintage! Another issue identified was that at the time of its installation, the cabling had been inserted into protective rubber hoses, which over the course of time had become as hard and brittle as cast iron, and this made the removal process more tedious. My curiosity was kept up though, with the discovery of an erroneously 'un-soldered' wire in the no.1 end of the car, betraying the idea that 488's motormen would have found the no.1 end a different drive to the no.2 end, because the offending 'dry joint' was in the braking circuits, so passengers would have had a slightly rougher ride in one direction!

After identifying the purpose of each wire, stripping out the antique wiring was slowed somewhat by the quantity of peculiar modern PVC wiring I came across, which was evidently installed for some form of lighting display during the car's exhibition by the Paris transport museum [AMTUIR].

As for the other electrical and semaphore wiring, it was sad to see just how unceremoniously it had been chopped out and new wiring added in antiquity, but at the time, the car was merely operating as a business, so neatness and a sense of finishing the job properly may have had to go by the board.

My work on re-wiring the lower saloon of the car is progressing well. As to the high current wiring for the controllers which I will be installing soon, this has already been allotted ducts down each side of the saloon, and owing to its flexible nature, it will not present undue headaches, except that the diameter of this cable is actually about twice that of the old - since double-insulated high current wiring having a flash test rating of 1000 Volts takes up a notable amount of space - and this can quickly consume duct space when there are several wires running parallel, as in 488's case.

At the time of writing, I have installed the wiring for all the lighting and bell signals. The wiring for the lights is being installed by a simpler route than its predecessor - straight through the roof of the lower saloon - in order not to stress the fine finish that has been achieved by the carpentry team. I have installed traction voltage lighting wiring, rather than re-designing a preferential system of low voltage wiring, as this would be too complicated. However, due to the nature of the car's bell pushes as used for conductor signalling, these have been modified for low voltage use, which is the safer option and uses as much of the equipment already in place as possible, with the addition of a battery and charging circuit.

A minor debate and fact-finding mission is underway regarding the changeover switching and 'cleaners lights' switching, as these features seem to have varied from year to year in the so-called Glasgow 'Standard' cars, which were anything but 'standard'! By way of evidence, 'Standard' car 812 at Crich Tramway museum has slightly different switching to 488, so we are still working out a compromise, remaining as true to the original 488 as possible.

In installing the new lamp sockets in the saloon, a couple of other anomalies turned up. The request to "just plug a bulb into that socket" would have yielded frustration in olden times, as the standardised 22 mm bayonet socket hadn't yet been invented, and bayonet lightbulb fittings were available in three different sizes - two of which turned up in 488. To simplify matters, 488 is being equipped with 22 mm fittings throughout, as it corresponds with my stock of 120 Volt bayonet lamps! No voltage has been applied to 488 yet, because no circuits are complete or capable of being used until the wiring 'spaghetti' has been connected properly, to make it usable. The upper deck will have to be wired and completed before it can be connected into the lower deck. Suffice to say, things are taking shape at a steady pace.

Finally, aside from the wiring, the pressure tanks housed under the floor of 488 are found to be unusable, so new ones will be fabricated which will include some parts of the original tanks. My concern over this summer is to find out the true condition of the motors and truck.

In fact, I was back at Boston Lodge last Thursday, on a very bright sunny afternoon. I removed the cover from 488's truck to let it see the light of day again. The general condition of the metalwork looked very promising, and I wanted to look more closely at what would be involved in the re-gauging of the wheels on the axles. It seems that re-positioning the brake shoes will be a matter of moving shim washers along the shim shaft, so my only real concern is whether the axles will be up to having the wheels pressed out to their required gauge positions.

The motors themselves were well covered in rust as one might expect, but a little bit of wire brush work and WD40 soon started to assist with my inspections. The armatures appeared to be intact and the bearings of the motors appeared free, although that doesn't mean to say that the bearings are good. The truck wheels haven't turned yet, so I was only able to move the armatures within the tolerances of the cog play within the drive cogs, which amounted to turning each armature about half an inch. I was very pleased to notice that the motors' cogs and axles' cogs were rust-free and had a reassuring covering of oil that had obviously protected them all this time.

Unfortunately, during my inspection I found that the brush gear in the motors was in a more sorry state, as the manufacturers had decided to use aluminum cups covering the brush gear, and aluminum doesn't do 'time' very well. Out of the four brush covers, three were seized solid, but I managed to animate the fourth one, and verified that the tension spring assembly was in tact and functional. Unfortunately, two of the shell springs that had been used to retain the brush covers had rotted away, and the other two had suffered badly. These will all be replaced.

On my next visit to the truck, I will be removing all the brush gear and taking it away for refurbishment. At this time, I am expecting the truck to take up its new residence in one of the carriage sheds at Boston Lodge, where heaters will be applied to determine the exact state of the windings in the motors. It is evident that this truck had been maintained in its life, borne out by the fact that all dash pots still had oil in them. What a welcome discovery!




Ray Maidstone
488 Technical Consultant