Top speed of bi / Tri modal trains on electric

[FlyingPotato]

How fast could the top speed of a bi mode train be, I know 800s have a speed of 140mph, but could you get a bi mode with a speed on electric of 186mph within out loading gauge

 

[CarrotPie]

How fast could the top speed of a bi-mode train be? I know 800s have a speed of 140mph, but could you get a bi-mode with a speed on electric of 186mph within our loading gauge?

Depends on how much passenger accommodation you want, really.

 

[hexagon789]

How fast could the top speed of a bi mode train be, I know 800s have a speed of 140mph, but could you get a bi mode with a speed on electric of 186mph within out loading gauge

Spain has ones which can do 250km/h (155mph) on electric, these have eketric power cars and a diesel generator cars either end of a rake of trailer cars rather than being distributed power like the 80x.

However, does the last portion of your post mean within the UK loading gauge?

Theoretically the 80x could be upgraded to 155mph, as overspeed testing to 154mph was performed on the design and there have been a couple of overspeed incidents into the mid-140s...

 

[ac6000cw]

Dynamic track forces increase as speed increases, as does energy consumption, so fitting powerful enough engines and carrying enough fuel for a decent range on diesel power becomes a problem due to weight/axle load limits for high speed running.

 

[hexagon789]

Dynamic track forces increase as speed increases, as does energy consumption, so fitting powerful enough engines and carrying enough fuel for a decent range on diesel power becomes a problem due to weight/axle load limits for high speed running.

I think the OP meant higher speed on electric mode only, not diesel. (Presumably retaining a 125mph diesel mode capability.)

 

[FlyingPotato]

Electric is what I meant as when I said could a bi mode reach electric speeds of 186mph

 

[ac6000cw]

Yes, but the weight/axle load penalty of carrying around diesel engines and fuel could affect the maximum speeds in electric mode too - that might be why the bi-mode Spanish Renfe Class 730 mentioned above (with an 18t max axle load) are limited to 155mph.

But the Americans have 125mph diesel locos with 30t axle loads and 135mph (design speed) electric locos with 27t axle loads so who knows?