Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Oct 5, 2014 9:14:07 GMT
I noticed just outside of Chalfont & Latimer 2 stop signals very closely spaced to each other and I thought why are they so close to each other.
What is the purpose of them so close together?
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Oct 5, 2014 9:28:53 GMT
JT83 and JT83 co-acting - for the Chesham single line.
|
|
rincew1nd
Administrator
Junior Under-wizzard of quiz
Posts: 10,286 
|
Post by rincew1nd on Oct 5, 2014 18:43:31 GMT
JT83 regulates entry to the Chesham branch, and is held at red until it been proved that a train has exited the section (AIALTB). JT83(Co-A) is provided as it is absolutely essential that a train does not pass the signal at red, I suppose similarly so to how buffer stops are provided with more than one red light - it's not just "Stop - Danger" it's "Stop - Peril".
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Oct 5, 2014 18:56:02 GMT
I always thought the co-acting signal was provided because, back in the day, trains could approach from the bay and the northbound main and the co-acting signal improved signal sighting. Was that just a myth?
|
|
rincew1nd
Administrator
Junior Under-wizzard of quiz
Posts: 10,286
|
Post by rincew1nd on Oct 5, 2014 19:20:51 GMT
I always thought the co-acting signal was provided because, back in the day, trains could approach from the bay and the northbound main and the co-acting signal improved signal sighting. Was that just a myth? Well, I guess any co-acting signal is there to improve sighting. However in this case trains from both the main and bay travel along the branch line for a fair way before reaching JT83, so I don't see how either the main signal or the co-acting could provide improved sighting for a train from either origins. |
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Oct 5, 2014 19:36:51 GMT
After googling, I gather that you are quite correct. DistrictSOM provides the answer here. Always good to be disabused of a wrong answer =) |
|
