Converting EMUs to Bi-Mode with Locomotives

[Dai Corner]

We've seen the difficulties experienced in fitting Diesel engines to EMUs to make Cl 230s and 769s

Why wasn't the idea of a small loco with compatible controls considered instead? Older readers will remember Cl 33s hauling / propelling EMUs between Bournemouth and Weymouth pre electrification.

The EMUs wouldn't have to be taken out of service for conversion. It would just be a matter of coupling up a loco and driving away.

One possible issue is platform length vs train length in some places but how long would the loco need to be to accommodate a suitable power unit? I'm sure people will come up with other snags!

 

[furnessvale]

We've seen the difficulties experienced in fitting Diesel engines to EMUs to make Cl 230s and 769s

Why wasn't the idea of a small loco with compatible controls considered instead? Older readers will remember Cl 33s hauling / propelling EMUs between Bournemouth and Weymouth pre electrification.

The EMUs wouldn't have to be taken out of service for conversion. It would just be a matter of coupling up a loco and driving away.

One possible issue is platform length vs train length in some places but how long would the loco need to be to accommodate a suitable power unit? I'm sure people will come up with other snags!

Rather than a loco with cabs etc, how about a new intermediate diesel coach as being fitted in (Stadler?) units in East Anglia.

 

[Dai Corner]

Rather than a loco with cabs etc, how about a new intermediate diesel coach as being fitted in (Stadler?) units in East Anglia.

Great idea, yes.

Being new build it could be properly designed and deployment would presumably just be a few hours in the depot.

 

[43096]

We've seen the difficulties experienced in fitting Diesel engines to EMUs to make Cl 230s and 769s

Why wasn't the idea of a small loco with compatible controls considered instead? Older readers will remember Cl 33s hauling / propelling EMUs between Bournemouth and Weymouth pre electrification.

The EMUs wouldn't have to be taken out of service for conversion. It would just be a matter of coupling up a loco and driving away.

One possible issue is platform length vs train length in some places but how long would the loco need to be to accommodate a suitable power unit? I'm sure people will come up with other snags!

How do you get power to the EMU for heating, lighting etc etc?

 

[Dai Corner]

How do you get power to the EMU for heating, lighting etc etc?

Same as way as you get it to trailer cars when they're operating as EMUs. How did the 4TCs get it from the Cl 33s?

 

[43096]

Same as way as you get it to trailer cars when they're operating as EMUs. How did the 4TCs get it from the Cl 33s?

They had ETH jumper cables. Current EMUs don’t.

 

[furnessvale]

They had ETH jumper cables. Current EMUs don’t.

I would presume if you were spending serious money building diesel power units (locos or inserted cars), the cost of fitting through power cables would be taken into account.

 

[60019]

Many modern designs don't use separate ETH lines, they convert from the traction supply in each carriage, since they've got the power connection anyway.

Making an auto coupler with compliant HV-DC bus connections would be tricky, which is a problem for most EMUs (though if it could be done, it would avoid the need for multiple pantographs on trains, cutting the cost of electrification). 750V DC connections would be workable, but would need chunky connectors to handle the current. For a semi-permanently coupled add-in like the Flirts, that's not a problem for any reasonably modern unit, because there's a power distribution bus and with fixed couplings you don't need automatic connections.

 

[edwin_m]

Many modern designs don't use separate ETH lines, they convert from the traction supply in each carriage, since they've got the power connection anyway.

Making an auto coupler with compliant HV-DC bus connections would be tricky, which is a problem for most EMUs (though if it could be done, it would avoid the need for multiple pantographs on trains, cutting the cost of electrification). 750V DC connections would be workable, but would need chunky connectors to handle the current. For a semi-permanently coupled add-in like the Flirts, that's not a problem for any reasonably modern unit, because there's a power distribution bus and with fixed couplings you don't need automatic connections.

AC EMUs don't send 25kV to each car, because (for the older designs we are discussing here) there is only one transformer on the same car as the pantograph, so the power for the auxiliaries must be sent down the train at a much lower voltage than 25kV. This makes auxiliary supply from a coupled locomotive or a new intermediate diesel "power car" possible in principle. DC and dual-voltage EMUs have a DC traction bus that links the shoegear on the end cars to the car(s) with the motors, so with these a diesel locomotive or non-motorized power car could also supply traction power.

 

[Mogz]

Interesting idea. I’ve always thought that 2 x 444s with a buffet open, hauled by a 67 or 68 would make a marvellous all-purpose long distance train from, for example, the North to the South Coast. Loco could come off at Basingstoke. Much nicer than a Voyager!

 

[Meerkat]

Interesting idea. I’ve always thought that 2 x 444s with a buffet open, hauled by a 67 or 68 would make a marvellous all-purpose long distance train from, for example, the North to the South Coast. Loco could come off at Basingstoke. Much nicer than a Voyager!

Make it a AC/DC unit and the loco could just do Basingstoke to Brum on the Manc-Bournemouth trains!

 

[Mogz]

Make it a AC/DC unit and the loco could just do Basingstoke to Brum on the Manc-Bournemouth trains!

Very true!

Alternatively using a Class 88 would also have a similar effect in reducing diesel emissions!

 

[Meerkat]

68 on one end, 88 on the other - and we are almost back with the original IET plan.....