JT83 Co-acting signal

The link there provides a few interesting insights, especially with regard to the GW railcars. If it's ok I'll copy one section of that to the KESR FB group as they have one of the surviving railcars there.

The question of co-acting signals has cropped up on a couple of different groups including this one I think regarding York Road station and the KX Widened Lines down starter. Co-acting signals were placed on opposite sides of the running lines at KX and York Road for the basic reason that steam locos could be either right hand drive or left hand drive. Hence the driver would see the signal regardless of what side he had to drive on. I can't remember whether the Chesham line co-acting signals were either side of the line, I haven't worked on that line since 1974! I can't see the point of co-acting signals being put on the same side of the line.

Regarding trip cocks on steam locos, the other thing the contributors to the other post have forgotten is that goods trains in steam days were generally unbraked, the driver relied on the loco brake and the guard to stop the train. If the loco was fitted with a vacuum brake, then the opening of the trip cock would apply the vacuum brake which also controlled the steam brake on the loco. Very few steam locos were air-braked, mostly GE designs in the London area.

Working unbraked or partially fitted goods trains required a high degree of skill on the part of the driver. He had to be carful pulling away so as not to cause too much of a snatch for the guard who was a train length away. Wagons were loose coupled with a gap between buffers. Stopping such trains required careful feathering of the loco brake to buffer up the wagons, again to avoid shaking the guard up too much!

Stopping distances were a lot greater than that of EMU stock as I found out the hard way when as a secondman at Rugby in 1975 I was invited to drive a class 25 with an unfitted train on the Southam branch. From 25mph it took over a quarter of a mile to stop 30-odd wagons.

It was "normal practice" for drivers of steam(and later diesel) goods trains to keep the trip cock isolated to prevent the shocks to the train mentioned above. When I was secondman at Kings Cross in 1976 my job at York road was to jump down and make sure the trip cock was down, the isolator handle was opened and let the driver know. The trip cock tester not only ensured it was within gauge but was actually down, hence the blue light adjacent to the tester and under the co-acting signal. The block end suburban stock was vacuum braked, so application of the trip cock on the loco would apply the brake evenly through the train. The fireman or secondman also had a duty to keep a sharp look out for all signals.

The operation of unfitted freight trains and varying length passenger trains on lines that carried BR traffic is also the reason these lines were fitted with the yellow disc distant signals. In common with BR practice, they would only show clear if the stop signals for the section in advance all showed a proceed aspect.