Page 1 of 1
| Another Brighton overlap puzzler 27/08/2011 at 23:17 #20238 | |
Forest Pines
525 posts |
This is another one of those "it *might* be right, but it doesn't feel right" issues. I have a track circuit failure on the up main across Preston Park junction, locking the advance part of the route from 430 to 422, including the overlap at 422. To be precise, of the 5 tracks shown on-screen that make up that route, the second was failed leaving the third, fourth and the overlap locked. A 1Hxx train then approached from Hove, so I signalled it into P1 on a warner route, expecting it to have to wait in P1 until the failure was fixed. However, after the 1Hxx train had been sitting at 420 for long enough that it had already phoned in, the overlap at 422 dropped. I didn't see it happen, but, as this was a while after the failure had originally occurred, what I suspect may have happened is that: the train standing at 420 triggered the timer for releasing the overlap at 422. Is this possible? And is it a design feature? Update: I have realised what had happened - this is why one shouldn't try to report things at 1am. I'd talked a train through on the up main, and when it passed 422 that had the effect of releasing the previously-locked overlap track. Is this correct behaviour, though? Last edited: 27/08/2011 at 23:26 by Forest Pines Reason: Stupid me Log in to reply |
| Re: Another Brighton overlap puzzler 28/08/2011 at 07:19 #20243 | |
|
Firefly
521 posts |
Hi Forest Pines What I believe has happened is the Overlap released whilst you had a train in Platform 2 (The one you talked by?) It seems that the simulation will release the overlap whenever the Platform 2 track circuit has been occupied for 40 seconds provided the route from 430 signal has been cancelled. Quote: Update: I have realised what had happened - this is why one shouldn't try to report things at 1am. I'd talked a train through on the up main, and when it passed 422 that had the effect of releasing the previously-locked overlap track. Is this correct behaviour, though?It wasn't the passing of 422 that released it, it was the fact that the platform track was occupied for 40 seconds. Take a look below:- This is how I believe you started off.  Train is now in Platform 2 and 430 Route has been cancelled  After 40 seconds the overlap releases.  You'd not of seen it release if you had the forward route set from 422. An interlocking of Brighton's vintage would behave in this manner. Modern practice would prevent the route release if any track circuits are occupied between 430 signal and the platform track. FF Post has attachments. Log in to view them. Last edited: 28/08/2011 at 07:28 by Firefly Log in to reply |