Post by Deleted on Aug 14, 2015 19:18:46 GMT
Occasionally on signalling diagrams I see a "wrong road signal & train stop". The signal is depicted as a white disk with a black spot in the middle, or - seemingly - a fixed red light. You can see one, for example, in Harsig's Central Line Eastern Extensions 1946-1957 diagram. If you look at the diagram of Liverpool Street, you can see one on the eastbound road between LB4 (station starter) and A461. There was, apparently, also one on the Northern line north of Hampstead on the northbound road, beyond the crossover and between A148 and A150.
My question is, what on earth were these and what functions did they serve? They do indeed appear to be for the wrong direction. You can see on Harsig's diagram the signal is drawn as though facing a train heading west along the eastbound. Similarly, on the Northern diagram at Hampstead, the signal is drawn as though facing a train heading south and the trainstop is drawn such that it would be on the right for a train heading south. But these signals are a long way past any point where I would expect trains to be travelling wrong road. In Harsig's diagram of Liverpool Street you can see the signal is some way along the eastbound road and there doesn't seem to be any valid reason for a train to be heading west at that point. Again, on the Northern, north of Hampstead, this "wrong road signal" is a long way north of the crossover, far beyond the shunt signal F9 which cleared trains over the crossover for a valid north-south move. Why would a train continue, pass A148 and then stop in rear of this "wrong road signal"? Or else, why would it have travelled south along the northbound all the way from Golders?
My question is, what on earth were these and what functions did they serve? They do indeed appear to be for the wrong direction. You can see on Harsig's diagram the signal is drawn as though facing a train heading west along the eastbound. Similarly, on the Northern diagram at Hampstead, the signal is drawn as though facing a train heading south and the trainstop is drawn such that it would be on the right for a train heading south. But these signals are a long way past any point where I would expect trains to be travelling wrong road. In Harsig's diagram of Liverpool Street you can see the signal is some way along the eastbound road and there doesn't seem to be any valid reason for a train to be heading west at that point. Again, on the Northern, north of Hampstead, this "wrong road signal" is a long way north of the crossover, far beyond the shunt signal F9 which cleared trains over the crossover for a valid north-south move. Why would a train continue, pass A148 and then stop in rear of this "wrong road signal"? Or else, why would it have travelled south along the northbound all the way from Golders?
