Dear Raam...
There is a big discussion on IRFCA on " In what circumstances LP are allowed to over speed."
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Here is one LP post on this matter. Hope it clears the matter.
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Dear Sirs,
First, i would like to thank all our friends for emphasising the fact, that the LP's are never allowed to overspeed. Again, Sri.Khalid had clearly stated the difficulties which may arise upon discussing this kind of topic in an open forum like ours. Now, coming to my point of view, i am not aware about the speedometers provided in...
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WAP5/7's working these Rajdhani's, but am very well aware about the Medha speedometers fitted in WDP3A's. They are very accurate, ( the error side is very minimal..) and as a LP seeing them for years now, i will say that they are really good. Few years back, Some GPS based speedometers were fitted on WDP3A loco's ( of GOC base) and i have seen that they always tend to show slightly lesser than the Medha ones on low speeds, and as the speed increases, they tend to catch up with the medha ones and when on high speeds, say 110-120 level, they tend to show 5-8 kmph more!! ( showing 125-128 when medha shows 117-120) As a curious person, i have personally checked the actual speed manytimes by distance travelled/time taken formula, with the help of my watch, and have got confirmation everytime, that the Medha speedometer is perfect.( say close to accuracy).
Again, I am not so thorough with SIMRAN, but i will share one recent incident with you. When i worked TVC raj in the last week, the Guard of the train had asked me twice, that at what speed i am driving at that moment. Then, on arrival, when i asked him about his query, he informed me, that one Speedometer has been fitted in the Guard van, and it was showing about 5 Kmph more than the MPS!!. ( Now, i realise, that it may be a SIMRAN too!!). But as a learned man of the section, my guard had cross checked the actual speed himself by the regular formula, ( as we have a fairly long stretch, 170 kms, with out a speed restriction, and i was maintaining MPS easily)
and satisfied himself that my speed as per the loco speedometer was correct. hence, he didnt bother much about it later. ofcourse, this was possible because, the RAJ runs on daytime in KR and it would be difficult for any guard to cross check if it was during night.
Sir, The LP's and Guard's working Rajdhani must have put upon years of good service with sufficient experience on that section they work daily. if there is overspeeding, then it will be known to 3 people immediately, as they will be continuously monitoring the same. 1) LP, 2) Guard and 3) most importantly the section controller. all these 3 persons must be well aware of minimum running time between every block station ( we call it as sectional clearance time too!!) and as they work regularly, they must be ready in mind about what exact minute they will pass the next station.( say, if there is no temporary speed restriction imposed in between). In case of overspeeding on a constant manner, you cannot avoid gaining time and since the LP and guard both maintain their journals physically, this factor can never go unnoticed. The same is the case of the controller too.
In the case mentioned by our friend Neerav, i wonder what was the actual time taken by that train to cover this section. was there any phenomenol decrease in time?.. In anycase, the Lp's will be adhering to the Speedometer in their cab, and i am sure that there cannot be an error percentage of +/- 2-3 kmph at the max, in this digital era. ( most of the speedometers get their drive from the Axle-Pulse generators). Regards,
Sampathkumar
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Source : IRFCA