(13-06-2010, 04:51 PM)KonduriRaghavakumar Wrote: Thank you sir, We generally call RE area(Railway area which is electrified by 25KV Over head equipment (OHE). In this area we use only single rail track circuits because of which one rail is given for return current from the OHE when the train passes. In this RE area track circuit the OHE department should have to provided the bonds (transverse bond, longitudinal bond, Z-bond ) for every track circuit portion. If this bond is missing there may be chance of return high current flowing through our bonds or track relays. Staff should ensure this also
Interesting info. The UK also use single rail track circuits in areas of 25kV electrification; however where on 660/750V dc then the currents are too high and get too much volt drop unless tracks very short. Therefore apart form tracks over point work then have the complication of double rail for dc traction current return and impedance bonds to keep the ac track circuit current separate.
I hope you can see that if you had worked this into your written answer that you'd not only have explained better but also have had the relevant material re risks and mitigations. In the UK we colour the very critical bonds red; if they become detached then could present hazardous voltage. Similarly where we are forced to have parallel rather than series bonding of the rails within a track circuit we provide multiple "parallel bonds" and these are coloured yellow (since if become disconnected they aren't self-revealing by producing rightside failure but are a latent fault)
Quote:Actually it will be good that i explained about the erection of the signal post and installation of point machine and installation of power supply to the equipment room.
The power supply system generally in our practice is we use a 10KVA step down transformer which taps supply from 25KVA Over head line which gives output of 230v in turn it is tapped to Electrical control panel where we use 230V AC as our input to equipment room either IPS (Integrated power supply system) system or conventional (charger with battery bank) system.
Whereas in dc areas taking a feed off the traction is commonplace, I don't think it is in 25kV areas in UK. The modern practice is for the signalling/ power demacation to be at Functional Supply Points that feed 650V to adjacent signalling location and for the power distriution along the railway (sometimes 650V sometime 415V) to be undertaken by the electrical rather than signal engineers. This is the sort of reason why it is worth summarising; it can avoid misunderstandings when examiner marking your paper and also illustrates that you know that the situation is not the same the world over.
Quote:During installation of point machine in case of providing fan-shaped layout with sleepers, layout will be assembled by p.way staff outside and a crane will be bought which inserts the assemble layout in the required position.
Indeed if there is relaying of the pointwork itself is involved then this is one of the methods which might be used in the UK; recently the continental practice of pre-assembling "modular" P'way in a distant factory (including all the signalling components) and bringing to site on rail vehicles is becoming more common.
Quote:The Station working rules document includes:
a) the normal operational procedures signaling system once it is installed,
b) the operational procedures in degraded conditions and
c) information related to the signalling plan, gradient, no.of level crossing gates whether these are interlocked or non interlocked gates.
What you have now written on this is just great; a sensible level of description to give a clear idea re what you mean, without wasting too much time on irrelevant detail.
To make it fit this question and on the assumption that you are saying no service trains would run during the commissioning, then you would need to explain why relevant; this could be because there are engineering vehicls needing to move in the area so roads may need to be crossed and there may be risks of unattended trolleys or ones with defective brakes running away on a gradient (we have had a couple of very serious such incidents in the last few years in the UK....)
Quote:In this RE-area there may be chance of getting the signals infringing with the track not as per the prescribed distance from the centre of track (i.e3.5 mts). While erecting such signals care should be taken that the OHE supply should shut down which not gives the induction effect.
One risk is the termination of tail cable with safe climbing of signal post.
I think you are getting the idea now of the sort of things that you should have said. Indeed I did say that I thought you had the experience and knew the relevant information but just had not written it- seems as if I was right! However the examiner can only mark what you do actually write- remember that!
Quote:Actually I did not have that much idea about the documents which shows that the safety is ensured during block period. will you guide me?
Certainly but it may be best that we see if someone else has a go at this portion first and then we can discuss; any offers?
