The Westinghouse brake system fitted to 6029 is the number 6 type. Originally designed as the next generation, state of the art system, it was first used on the diesel powered Burlington Railroad Zephyr high speed rail motors of the 1930’s. It was adapted to Australian use in the 1940’s as the A6 ET type. A denoting Australian, 6 being the system type and ET denoting engine and tender. Later versions would also have 3 and 4 control pipes that would allow the driver of the leading locomotive to apply and release the independent locomotive brakes when double heading etc. Naturally 6029 does not have a coal tender but for all other purposes she is fitted with a A6ET brake system. Maybe it could be renamed A6EB, the B denoting a bunker, but that would be a little over the top.
During the winter months, many of the small brake components are being overhauled off site. The first of the brake components to be tackled is the air compressor. This vital piece of equipment is probably the most important sub assembly on the locomotive second only to the boiler. For instance if the air compressor fails in traffic the locomotive is effectively un-serviceable until it is fixed. From the outset is was decided to completely overhaul the compressor to the highest possible standard to ensure that as far as possible,it will give reliable service.
Presently the air compressor has been stripped down to the last nut and bolt. All of the cylinder bores were measured and although still within limits it was decided to machine all bores back to completely parallel. Both of the piston rods have been hard chromed with only new piston rings to be ordered. When fitted 6029’s compressor will be almost better than new and we anticipate many years of trouble free operation.
The distributing valve has been stripped for assessment. As suspected it was full of gummed up dirt and grease. The triple valve portions piston ring was seized solid. These rings are very expensive to replace and very easy to break. After soaking the ring and piston in acetone for a few days it eventually freed up. The relay portion is fitted with a neoprene cup seal. This seal was found to be in good condition and will be ok for future use. The usual primer and 2 coats of black enamel have been applied in preparation for assembly and eventual testing.
The duplex air compressor governor, feed vales x 4 and the drivers brake valves will be next on the list. Looks like there will be many more hours work in the shed this winter.
Alan Gardner
