Post by Deleted on Apr 30, 2014 23:34:59 GMT
Hello everyone,
As a Central line commuter, I'm quite interested in understanding a bit more about the system that gets me in to the city (unless it's raining, obviously) and, naturally, the underlying ATP that's looking after me when I'm treated to a journey in Coded Manual. Unfortunately, for me at least, information seems rather hard to get hold of. Of course, I could just be doing a bad job of searching, in which case I'd be delighted if someone could point me in the right direction.
Rather than just post an open-ended thread and expect someone to come along and tell me everything, though, I thought I'd probably better ask some actual questions. One article that has been very helpful to me - I'm sure many of you will have seen it, can be found on the website davros.org. This article does leave me with quite a few questions, though, and if I might, I'd like to see if anyone can help me.
In that article one of the things it points out is 'The codes are always arranged to provide a clear overlap beyond the end of a section which is appropriate for the current speed limit of that section.' My question is how this is achieved at a place like Woodford and, in fact, how Woodford is operated. The site is very good, but it's quite cursory and seems mainly to focus on automatic sections.
So, allow me to make it more specific. At Woodford, on the westbound track you have a crossover immediately outside the station. Just in rear of that is a block-marker board. Within the platform (westbound platform 2) limits there are two more block marker boards and then there's the semi-auto station starter, with junction indicator. Plainly the blocks within the platform are much shorter than a train length and I wonder how they operate.
It is also clear that an entire block is not left as an overlap at Woodford. When there is a train in the platform, it is possible for a train to stop at the block marker board just in rear of the crossover, but, as far as I'm aware, there is no overlap block, the next block extends into the platform, where the train is. Perhaps a diagram would help, particularly for those not too familiar with the area. I jotted down the numbers when I was at Woodford today and I may have made a mistake, but I think these are right. Also, obviously, I can't see out of the front, so if I've made a mistake and have overlooked a block marker board or signal, I do apologise.
Obviously the blue boxes represent trains and I hope my representations of the signals and block marker boards are good enough to not require explanation.
The other thing I notice at Woodford very regularly is a train coming out of 21 road (the siding at Woodford used to reverse trains arriving via Hainault and as the shunting neck (I think that's the right word) for the sidings as well as providing access to platform 1) while a train pulls in to platform 2. I notice some kind of speed control seems to be employed and I'm interested to know how that's achieved. Again, no overlap block is used, I notice, since the train leaving 21 road for platform 3 passes through the block ahead of WOO 7266 (the station starter) as it does so, even as a train arrives in platform 2. I was just wondering how that was achieved.
Sorry, I know that's quite a lot for one post, I had intended that everything would fit together and would form a coherent whole question and I hope I've managed that and I hope it's obvious how each question is linked and what I'm asking for.
I understand that this might take some answering and if I should simply do some more reading I'd be quite happy just to be pointed in the right direction.
Many thanks!
As a Central line commuter, I'm quite interested in understanding a bit more about the system that gets me in to the city (unless it's raining, obviously) and, naturally, the underlying ATP that's looking after me when I'm treated to a journey in Coded Manual. Unfortunately, for me at least, information seems rather hard to get hold of. Of course, I could just be doing a bad job of searching, in which case I'd be delighted if someone could point me in the right direction.
Rather than just post an open-ended thread and expect someone to come along and tell me everything, though, I thought I'd probably better ask some actual questions. One article that has been very helpful to me - I'm sure many of you will have seen it, can be found on the website davros.org. This article does leave me with quite a few questions, though, and if I might, I'd like to see if anyone can help me.
In that article one of the things it points out is 'The codes are always arranged to provide a clear overlap beyond the end of a section which is appropriate for the current speed limit of that section.' My question is how this is achieved at a place like Woodford and, in fact, how Woodford is operated. The site is very good, but it's quite cursory and seems mainly to focus on automatic sections.
So, allow me to make it more specific. At Woodford, on the westbound track you have a crossover immediately outside the station. Just in rear of that is a block-marker board. Within the platform (westbound platform 2) limits there are two more block marker boards and then there's the semi-auto station starter, with junction indicator. Plainly the blocks within the platform are much shorter than a train length and I wonder how they operate.
It is also clear that an entire block is not left as an overlap at Woodford. When there is a train in the platform, it is possible for a train to stop at the block marker board just in rear of the crossover, but, as far as I'm aware, there is no overlap block, the next block extends into the platform, where the train is. Perhaps a diagram would help, particularly for those not too familiar with the area. I jotted down the numbers when I was at Woodford today and I may have made a mistake, but I think these are right. Also, obviously, I can't see out of the front, so if I've made a mistake and have overlooked a block marker board or signal, I do apologise.
Obviously the blue boxes represent trains and I hope my representations of the signals and block marker boards are good enough to not require explanation.
The other thing I notice at Woodford very regularly is a train coming out of 21 road (the siding at Woodford used to reverse trains arriving via Hainault and as the shunting neck (I think that's the right word) for the sidings as well as providing access to platform 1) while a train pulls in to platform 2. I notice some kind of speed control seems to be employed and I'm interested to know how that's achieved. Again, no overlap block is used, I notice, since the train leaving 21 road for platform 3 passes through the block ahead of WOO 7266 (the station starter) as it does so, even as a train arrives in platform 2. I was just wondering how that was achieved.
Sorry, I know that's quite a lot for one post, I had intended that everything would fit together and would form a coherent whole question and I hope I've managed that and I hope it's obvious how each question is linked and what I'm asking for.
I understand that this might take some answering and if I should simply do some more reading I'd be quite happy just to be pointed in the right direction.
Many thanks!
