28-08-2018, 09:10 PM
Hi People,
Apologies if this has already been covered somewhere and i have missed it but there was no folder for the 2017 exam attempts.
I am struggling with question 1c on exam paper 2017 (extract attached)
I know the bidirectional single line working tunnel is the limiting factor on capacity but i am struggling to put this into numbers for trains per hour.
My signalling layout gives a total single line section of 5540m.
This is a combination of 200m (from controlling signal to tunnel start) + 5300m (tunnel length) + 140m (to route releasing track circuit)
The speed of a train on the branch is 90kmh^-1 which = 25ms^-1.
Therefore the time to get through my single line section is 222 seconds.
I then multiplied this by 2 (222 x 2) to allow time for a train heading on the up branch to cross through the tunnel.
I then did 3600/ 444 = 8 trains per hour.
can somebody tell me if i have the right idea?
I assume that for this branch line i should use 2 aspect signalling with a block length near to the maximum 2 x braking distance?
I will get my layout scanned into the system by thursday so will also upload this for some comments shortly.
Thanks in advance to anyone who might be able to provide some help.
Lee.
Apologies if this has already been covered somewhere and i have missed it but there was no folder for the 2017 exam attempts.
I am struggling with question 1c on exam paper 2017 (extract attached)
I know the bidirectional single line working tunnel is the limiting factor on capacity but i am struggling to put this into numbers for trains per hour.
My signalling layout gives a total single line section of 5540m.
This is a combination of 200m (from controlling signal to tunnel start) + 5300m (tunnel length) + 140m (to route releasing track circuit)
The speed of a train on the branch is 90kmh^-1 which = 25ms^-1.
Therefore the time to get through my single line section is 222 seconds.
I then multiplied this by 2 (222 x 2) to allow time for a train heading on the up branch to cross through the tunnel.
I then did 3600/ 444 = 8 trains per hour.
can somebody tell me if i have the right idea?
I assume that for this branch line i should use 2 aspect signalling with a block length near to the maximum 2 x braking distance?
I will get my layout scanned into the system by thursday so will also upload this for some comments shortly.
Thanks in advance to anyone who might be able to provide some help.
Lee.