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Indian Railways High Catenary to allow Double Stack on flat cars

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jis

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For those that keep bringing up the issue of difficulty electrifying routes that carry high freight cars, as it turns out Indian Railways has standardized on 7.57m (24.8") high catenary for routes that will be cleared to carry double stack freight trains. The normal catenary height in India is 6m (19.7').

Naturally high catenary requires more robust and bigger pantographs. Electric engines for use on high catenary routes are equipped with one pantograph of the larger size and the other one of standard size. Here is a video of a WAP-5 Class electric engine equipped with high panto operating on the Delhi - Rewari route (my old stomping grounds when I lived in Rajasthan in India).

 

caravanman

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Interesting, the larger panto does look odd at first glance. Is there any negative trade off, can the trains maintain the same maximum speed for example?
 
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jis

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Interesting, the larger panto does look odd at first glance. Is there any negative trade off, can the trains maintain the same maximum speed for example?
Apparently high catenary will not be deployed on higher speed trunk routes, which suggests that they are not viewed as conducive to high speed operations. Most likely has to do with aerodynamics of huge pantographs. That is also probably the reason that high catenary engines have one pantograph for high and one for low, to be able to operate at full speed on regular routes.

For example this WAP-5 in the video is capable of operating at 200kph. Unlikely that it will do so on a high catenary track.

Only select routes for double stack containers will have high catenary. Most routes won't. The Delhi - Rewari section is never going to be highers speed along this alignment and it is part of the Western Freight Corridor between Delhi and Mumbai via Ahmadabad. The Eastern freight Corridor from Ludhiana in Punjab to Dankuni just outside Kolkata via Delhi is an entirely separate freight ROW sharing no trackage with the current main line, mostly parallel to the current ROW via Grand Chord between Mughal Sarai (Ooops Pandit Deen Dayal Upadhyay Jn.) and Sitrampur (near Asansol) and then via Howrah Bardhaman Chord between Saktigarh (near Bardhaman) and Dankuni.

Oddly, at present the new, most powerful (12kHP), Alstom Prima based WAG-12s Bo-Bo-Bo-Bo are not equipped with the high panto, but there is ample roof space on these behemoths to add a high panto when needed. They have been seen operating a lot on Eastern and South Eastern Railway although their home shed is currently at Saharanpur in UP.
 

jis

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Also, as Jis states in the thread title, the containers are on flat cars, so they are taller than the American double-stacks on well cars.
Yes. Standard ISO Containers are 8.5' tall. Indian doubles stack trains will be 17' + 4' flat = ~21' tall, ~1' taller than American Plate H and K. They will fit just fine under the high catenary of 24.8' with plenty of clearance for 25kV and even for 50kV if they choose to go that route in the future, and not at all under standard catenary of 19.7'.

Interestingly, India went with flat cars rather than well cars in order to be able to pack the containers as tightly as possible length-wise, so as to carry the most number of containers on shortest possible trains since they do not plan to run a train that does not fit on a passing loop on a busy trunk route. They may do so on some limited segments of the Dedicated Freight Corridors which carry nothing other than unit container trains that would hopefully not require any passing. All DFCs are fully double track so crossing for opposing traffic is not an issue.
 
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Just-Thinking-51

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1st post video shows twin strands of wire, is that normal? Something to due with oversized pick up bar?

17 car train, nice.
 

cirdan

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Is there any reason they can't cover both heights of catenary with a single pantograph that just folds to different degrees?

Electrified railways already have tricks such as lower than standard catenary where the clearances won't allow for regular height. For example in the UK there are a number of bridges and tunnels that have restricted clearances. In some cases the electrification voltage is lessened accordingly to prevent risk of flashover (this is why some older locomotives were specified as dual voltage for 25kV and 6.25 kV - the latter being exactly a quarter of the former). In some cases there is a length of non-live wire even, which just serves to lead the pantograph. with the transition of height being gradual, the pantograph just folds and unfolds by itself.
 

caravanman

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1st post video shows twin strands of wire, is that normal? Something to due with oversized pick up bar?

17 car train, nice.
I think the angle makes it look like two panto wires, but I believe the second wire is actually above the panto contact wire, supporting it?
17 car trains are nice, but in India, many trains run with up to 24-26 cars. Always worth checking which end of the platform your seat will be, before the train arrives!
 

caravanman

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Is there any reason they can't cover both heights of catenary with a single pantograph that just folds to different degrees?
I don't know for sure, but assume that the height difference between the two wires might be just too large? Maybe the spring or hydraulic pressures needed to maintain correct contact at the top height would be too great and damage the wires at the lower height? Any mechanical engineers on the forum? :)
 

jis

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Is there any reason they can't cover both heights of catenary with a single pantograph that just folds to different degrees?

Electrified railways already have tricks such as lower than standard catenary where the clearances won't allow for regular height. For example in the UK there are a number of bridges and tunnels that have restricted clearances. In some cases the electrification voltage is lessened accordingly to prevent risk of flashover (this is why some older locomotives were specified as dual voltage for 25kV and 6.25 kV - the latter being exactly a quarter of the former). In some cases there is a length of non-live wire even, which just serves to lead the pantograph. with the transition of height being gradual, the pantograph just folds and unfolds by itself.
Dunno. You'll have to ask the folks at RDSO who researched this over ten years and came to this determination.

I suspect that there are both cost and technical factors. The high pantos are quite a bit more expensive and have much higher failure rate than the regular ones. apparently, and they do not behave well at higher speeds in any position. Generally IR does not recommend their use above 110kph.

But as I said, I don;t know the details for sure, and as is fashionable to say these days "it is what it is". :)
1st post video shows twin strands of wire, is that normal? Something to due with oversized pick up bar?

17 car train, nice.
There are two parallel catenaries in an overlap section where one catenary segment ends and the next one begins. The dead giveaway is the tension weight at a post just preceding the one where you see the two strands. So no there is no continuous two strands. The catenary is the usual lightweight single catenary single contact wire that is the standard on Indian Railways. It is just strung higher.
17 car trains are nice, but in India, many trains run with up to 24-26 cars. Always worth checking which end of the platform your seat will be, before the train arrives!
Yes. 17 car is a short train in India. Standard pretty much is 20 cars, with most major station platforms capable of handling 27 cars (Schlieren) or 24 cars (LHB). Passing loops can handle much longer and IR somehow has no qualms about running trains that do not fit fully on a platform here and there, if it will reduce over crowding.

Most platforms have coach position indicators and the coach number showed on them matches those on your reservation slip or on your eTicket on your smartphone. But yes, it is a good idea to position yourself under the sign indicating your coach number as soon as the coach numbers are posted.
 
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cirdan

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I don't know for sure, but assume that the height difference between the two wires might be just too large? Maybe the spring or hydraulic pressures needed to maintain correct contact at the top height would be too great and damage the wires at the lower height? Any mechanical engineers on the forum? :)
This sounds credible. I am sure there would be a way to work around that but maybe it would just have been too complicated.

I suspect that there are both cost and technical factors. The high pantos are quite a bit more expensive and have much higher failure rate than the regular ones. apparently, and they do not behave well at higher speeds in any position. Generally IR does not recommend their use above 110kph.
110kph? Isn't that a bit restrictive for something that's new? Or is this a temporary stop-gap and they are maybe figuring they will find a different solution if and when they decide to go faster?
 

jis

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110kph? Isn't that a bit restrictive for something that's new? Or is this a temporary stop-gap and they are maybe figuring they will find a different solution if and when they decide to go faster?
They are primarily for double stack container trains, with very little shared trackage with passenger trains. The Delhi - Rewari section at least for now is one of those rare shared track segments. Eventually when traffic grows they will add two separate freight tracks separating it out. But for now there is no justifications for additional tracks. Currently there are no plans to run double stack freight trains above 110kph (68mph), which is already way higher than the current normal 50mph. Push comes to shove I am sure they can be pushed upto 120kph. But they will never be run at 140+kph.
 
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Just-Thinking-51

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Ok I see the weights now, thanks.

Maybe someday we Americans can leave our country and go play tourist again.
 

west point

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At higher CAT heights a RR needs to make sure that one rail does not sag too much. A 3 inch sag of one rail would move the contact point ~ 15 inches off center. much more and pan might snag in CAT.
 
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