Whether a bi-mode Voyager would have been possible when they were under construction

[tomuk]

And I started the thread to determine whether or not the Voyagers could realistically have been built as high-speed bi-modes with the technology that ws available in the late 90s.

There is no question the voyagers could have been built as bimodes when new. There is no new technology on the 80x IEPs that wasn't available when the Voyagers were built.

 

[AM9]

There is no question the voyagers could have been built as bimodes when new. There is no new technology on the 80x IEPs that wasn't available when the Voyagers were built.

That's true but the essential difference is the experience of actually doing it, and the operational experience. Clearly the 769 project is a mixture of meeting a short-term need for DMUs and moving some way towards reduction of diesel under wires. But despite (or maybe even because of), the teething troubles of introducing them into full service, valuable experience is being gained on bi-mode operation. In the coming autumn and winter period, a valuable knowledge base will accrue that can benefit future plans for new bi-mode train acquisitions.

 

[David Bullock]

Was there a c.950bhp engine available in the 90s that could have fit under the floor of a carriage? There still isn’t a bi mode in service which can get to 125mph quickly (if at all) on diesel. I would imagine that maintaining the high power to weight ratio that voyagers have, alongside bi-mode gubbins and tilt capability would probably have been a bit much.

 

[Bletchleyite]

Was there a c.950bhp engine available in the 90s that could have fit under the floor of a carriage? There still isn’t a bi mode in service which can get to 125mph quickly (if at all) on diesel. I would imagine that maintaining the high power to weight ratio that voyagers have, alongside bi-mode gubbins and tilt capability would probably have been a bit much.

No, but Voyagers can run perfectly well with an engine out - their acceleration is already software-throttled to some extent* - so the existing engines would cope fine with a pantograph-trailer coach inserted.

* Anyone who experienced them in the early days can attest that they certainly have the power to match a fast EMU out of the blocks if they wanted to.

 

[LOL The Irony]

Was there a c.950bhp engine available in the 90s that could have fit under the floor of a carriage?

Voyagers only have a 750bhp engine.

 

[AM9]

Voyagers only have a 750bhp engine.

.... and that 750hp is a gross figure; unlike traction motors, there's no 'boost mode' based on them operating below their maximum temperature.

 

[tomuk]

You wouldn't necessarily need another car. A 4MW traction transformer is at most 5000kg you could fit this in place of one of the accessible toilets and associated tanks.