Amphibious Trains

[McColm]

I tried looking this up on the internet and the only reference is trains running on flooded sections of track which is not strictly an amphibious train.
I'm no engineer, if a ship can stay afloat then surely a train should be able to as well?
Displacement  and buoyancy is an issue but not in the whiffing world.
The scenario would be that the bridge spanning the river has collapsed, so the train using GPS should be able to float across by the momentum of it's engines or an alternative power source and link up with the track on the other side, depending on the slope of the riverbank. The locomotive would probably have a mechanism for this to happen.
However this wouldn't work on a fast flowing river.
Well it's just a theory, unless this has been tested before

[PR19_Kit]

Erm, there's one rather fundamental problem there.

Without the track there's no way for the loco, or other motive power vehicle, to transfer its power to the outside world, the wheels would just rotate aimlessly.

The thing that keeps ships afloat is their volume, which is a LOT more than a railway vehicle of any sort.

[McColm]

I've seen a video on YouTube that shows the Australian railbus system that uses both rail and wheels/tyres.
It's based on a coach rather than a locomotive.
So something like a DMU would be more suitable for this whiff.

[Gondor]

McColm, A train works because it transfers it's motive force through the wheels that are in contact with the track, same as a tram, similar thing for car's busses and lorries transferring their motive power through their wheels onto the surface they are in contact with. A train, if it could float, would need to have a means of transferring its motive power into the water and wheels that are used on tracks are not capable of doing that or anything else!

Gondor

[Weaver]

Not nest-of-celery folks: many military amphibians are propelled in the water by their wheels, so a _properly designed_ train wheel, say with paddle-like spokes/extensions, might be able to do it. I'd be more fundamentally concerned about buoyancy to be honest. Trains are notably dense, and any floation devices will have to fit through tunnels and all the other limitations that make up the loading gauge. I suspect you'd be looking at inflatable bags, and LOTS of them, as the only viable option.

Also, how are you going to control the motion of any carriages it's pulling, once they're in the water? When the train's climbing out of the river, the carriages will be carried downstream by the current...

[Snowtrooper]

Even if it floats, it's going to be tricky getting the train re-railed again on the other shore. Especially if you have to steer on dry land, or first drive over one rail and start turning so that the rails righten the rest of the train... and floating so straight that the train hits the beach exactly between the rails perfectly aligned is going to be even more tricky.

[Old Wombat]

An amphibious road train might be interesting, though!

[McColm]

As Kit will tell you, when he was a lad back in the Victorian days cogs and chains where used on very steep inclines. Hauling barges and trains, some of his handiwork is still in use today.
The driver would press a button that would shoot a grappling hook (s)on the bank and with a powered winch haul itself back up.
Power isn't the problem it's how to use it to cross the water. Now if the train had hydraulic legs attached to water skis, you could just drive across, similar to what they do in Iceland with 4x4's on lakes or ski-doos. If you ease off the power you will sink.
The tyre tread would be the secret as these would be designed to power through the water and keep the train from sinking. So a couple of detachable turbojets secured to the roof, should do the trick.
Besides, if the train is traveling at speed through the water it will only start sinking if it slows down or takes in water or runs out of fuel.
So anything below 55 mph and you are going by a bus replacement service.

[kerick]

Oh come on now! In the movie Polar Express the train makes it across the ice and up onto the rails on the other side! No problem! Call Tom Hanks for further advice.