29-08-2019, 08:58 AM
Thanks once again, really appreciate the comments. Its a been a bit quiet in the forum this year, and is always helpful to get some good feedback, especially this close to the exams. I Just made an assumption on dwell time, and also I did all my calcs with train leaving the down main as seemed like the easiest way to calculate the required headway. I thought about considering both train movements from their starting positions but decided it would add too much complexity for me to think about, especially under exam conditions. TF Wrote:REMBrum
Morning,
Looking at the response to question 1C, firstly I'd say check the diagram you've given- always good to give a diagram, but the question asks you to consider a stopping service leaving the down loop (rather than the down main). I don't think this affects the calcs in this instance.
Your calculations to understand the speed to reach linespeed for the stopped service look correct. The remaining calculations for the distance to the branch protecting signal and the linespeed calculations also look good (obviously the actual answer would be slightly different due to the signal distances, but your principles are sound).
My only other comment would be that you've added a 30 second dwell time when adding the overall time for the stopping train to reach linespeed and clear the branch protecting signal overlap. You could consider driver reaction time here for the driver to notice the proceed signal (approx. 5 seconds), but I'd say there's no need to consider a full dwell time- the question paper asks you to consider the headway following the departure of the stopping service only.
Good stuff, keep going!