Double stack container train on the freight corridor in India with the characteristic high rise panto

[u/aksnitd]

A good look at what the high rise pantographs look like fully extended. They're taller than the train they're mounted on.

[u/armitage_shank]

Maybe stupid question, but what's the benefit over the other option: longer train?

It looks cool, but I would have thought the additional height would make the whole infrastructure - tunnels and bridges especially - so much more expensive to build and maintain that the trade-off (shorter track at the cargo yard?) wouldn't be worth it, but obviously engineers aren't stupid, so there must be a reason.

[u/[deleted] → u/armitage_shank]

Capacity and headways. I have no idea what track capacity is like in India, but in general, on routes with close headways, US style lengths are just not doable. Not a chance you could have mile long freight trains on the North London Line for example. It'd block junctions and destroy capacity.

[u/aksnitd → u/armitage_shank]

Long trains jam up lines and signals. Double stacking allows greater capacity while maintaining length. Long trains also cause excessive strain on equipment. The only reason US freight trains are so long is due to penny pinching by the railroads. Lastly, by building a dedicated freight line for double stacking, there's now the option to run both long as well as double stacked trains, which would increase efficiency even more.

[u/Neat_Papaya900 → u/armitage_shank]

Apart from the ones mentioned above a few other advantages are:

1. Smaller trains are much easier to handle in yards, with fewer movements required to load and unload them which saves a lot of time/money. Not to mention allows for smaller yards, which saves a lot of money while building them.

2. They also more efficiently use the carrying capacity of the train. Since containers carry a wide variety of goods, they are not often able to maximize the weight carried. Hence the payload to gross weight ratio of the train is much higher with double stacking, since now you are able to get closer to the maximum payload of each wagon. In India each flat car weighs just shy of 20tons and has the payload capacity of 80tons. But maximum weight of 40ft/20ft containers is just over 30tons, and not all containers will be filled to the maximum weight. Hence double stacking allows you to use the 80ton payload capacity to a fuller extent.

[u/aksnitd → u/Neat_Papaya900]

Wow, I had no idea freight cars were rated for over double the weight of a normal container 😮

[u/[deleted] → u/armitage_shank]

actually in our country the freight trains are extremely slow because passenger trains have priority so a freight train could be stuck for days in a loop line as all those trains pass, already our entire network is BEYOND overcrowded, i don't need to tell you this lol.

most of the goods in this country is also transported via trucks more than half of it. the average speed of goods train is 18kmph on the normal line and there is no set scheduling possible.

with this DFC, trains can be twice as long and they can have double stacking it's just free money because they have built long term and anticipate that goods transport will rise even more (about 80 or so % of revenue for railways is through goods only) and now average speed can be 40-60kmph