28-08-2019, 02:59 PM
Afternoon TF,
The question paper for 2013 asks you to:
"Determine the minimum braking distances for the permissible speeds and braking characteristics of the traffic specified on layout 1". You've only detailed the headway braking distance.
I used a table to record all the permissible line speed braking distances using the same calculations you've applied to get the headway minimum braking. You don't necessarily have to demonstrate the working out each time for each line speed, just perhaps once so that you demonstrate the underpinning maths.
Your uniform minimum signal spacing will therefore be different for the branch and main lines and will be based on the permissible line speed braking distance rather than headway braking.
You might want to consider a simple diagram for the HT3 and HT4 calculations to show how the BSOL applies. The principles of the HT3 and HT4 calculations looks fine, however the minimum spacing should be PSR based rather than headway based.
I've attached the paper and layout for anyones reference.
Hope that helps
The question paper for 2013 asks you to:
"Determine the minimum braking distances for the permissible speeds and braking characteristics of the traffic specified on layout 1". You've only detailed the headway braking distance.
I used a table to record all the permissible line speed braking distances using the same calculations you've applied to get the headway minimum braking. You don't necessarily have to demonstrate the working out each time for each line speed, just perhaps once so that you demonstrate the underpinning maths.
Your uniform minimum signal spacing will therefore be different for the branch and main lines and will be based on the permissible line speed braking distance rather than headway braking.
You might want to consider a simple diagram for the HT3 and HT4 calculations to show how the BSOL applies. The principles of the HT3 and HT4 calculations looks fine, however the minimum spacing should be PSR based rather than headway based.
I've attached the paper and layout for anyones reference.
Hope that helps