(20-05-2010, 03:34 AM)KonduriRaghavakumar Wrote: Thank You Sir for your valuable suggestions, I just made one correction that fusee lit for only 7 minutes. Can you guide me what is the impact of operation on unaffected part of railway which i didn't understand.
If I had known about a fusee then I may have guessed that you used the wrong word; because I didn't, I had to take your words meaning what they appeared to. I am afraid that this is a disadvantage that you face. However you do have a corresponding advantage; your description may be slightly wrong but provided it is plausible I'd go with it; however I'd be far more critical of a UK student as I would be far more certain that they were wrong if they wrote something incorrect.
I know understand that a fusee is a form of flame torch carried by track workers as a means of stopping trains in emergency.
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Replacing signals to danger can be entirely selective; the signalman will only give the message to stop to those trains which are considered endangered by the emergency and those which could still run safely would not be affected.
The same could be true using radio message to stop one secific train; however a general "Emergency Stop" call would not cause the stopping of those trains wanted but also others as well.
Examples:
a) Perhaps the incident only affected one direction running line; train in the opposite direction would also be stopped.
b)Perhaps the incident affected a bridge- in this case trains in both directions would need to be stopped, but those that already had passed over the bridge and going away from it would also be stopped unnecessarily.
c) Perhaps the incident had occurred on the branch line just beyond the junction at the signalbox; there would be no need to stop trains on the mainline but a red flag or fusee at the signalbox would stop trains heading for the mainline as well as those heading for the branch. It would not protect trains coming from the branch as it would be encountered too late, yet trains from the mainline would see it and then stop even though they were not destined for the line with the incident.
Your method re stopping trains by cutting the power supply would have been a good one to illustrate this with; it is unlikely that the electrical contol has very precise remote switching and any urgent disconnection may well affect a wide area and thus be a "blanket outage" rather than able to be "targetted" to the incident area itself.
This gives another esson re doing these wrotten questions; "look for the hidden question" and address it. In this case it is
1. to recognise that there are a range of reasons for stopping trains in emergency; for e.g.
- is it to protect the train or
-is it to protect somone from the train
2. to recognise that the best means to use may depend upon the type of incident.
A candidate demonstrates their railway experience to the examiner by seeing the things which lie beneath the surface of the question and bringing them into the discussion. You make it relevant to what was "actually asked" by using a typicl range of incidents to address the art of the question asking abot "effectiveness" and "operation of the unaffected part".
You should have asked yourself: what emergency? what incident? which trains in that case would I want to stop? and which trains need not have been stopped?
So you may have considered incidents such as-
a) derailment on train on adjacent track which may be foul
b) member of public fallen off platform at station
c) underbridge hit by road vehicle
d) broken rail
e) staff attending broken down train on the runnuing line adjacent to other tracks
f) fire at a factory close to the tracks
g) terrorist alert at a major station
h) lorry stuck on automatic level crossing
j) herd of cows broken through fence and wandering around the railway track
Think of a list and then choose appropriate ones to illustrate elements of your answer to give you more concrete examples to talk about in order to explore the things that the examiners were asking you about
PJW