Can an EMU pull or tow a DMU that it's coupled to

[dcsprior]

I was wondering if it was possible where the economics of electrifying a whole route don't add up, to (as an alternative to bimode trains) have the DMU which has worked the unelectrified bit couple up to an EMU for the electrified bit, and then have the EMU push (or tow) the DMU the rest of the way?

For instance, if it wasn't worth electrifying the entirety of local line (the borders railway) could it be electrified at the Edinburgh end only, with trains coupling/decoupling somewhere like Gorebridge?

 

[Tynwald]

If it has a compatible coupling, and MU control system, then yes.

 

[swt_passenger]

I was wondering if it was possible where the economics of electrifying a whole route don't add up, to (as an alternative to bimode trains) have the DMU which has worked the unelectrified bit couple up to an EMU for the electrified bit, and then have the EMU push (or tow) the DMU the rest of the way?

For instance, if it wasn't worth electrifying the entirety of local line (the borders railway) could it be electrified at the Edinburgh end only, with trains coupling/decoupling somewhere like Gorebridge?

In principle yes it’s possible. A significantly overpowered EMU could haul a DMU. Your idea is only slightly different to the use of push-pull EMU operation on the Waterloo - Weymouth line, in that case they had a 4 car EMU (4REP) with enough installed power to push or pull 8 coaches (2 x 4 car sets with cabs - 4TC). Beyond Bournemouth the coaches were loco-hauled. You’d have to account for your DMU being heavier than ordinary coaches though.

 

[30907]

It happens, or used to, regularly in Denmark with Esbjerg-Copenhagen diesels attaching to an EMU when they reached the wires.

 

[Royston Vasey]

Isn't it the DMU that should most likely end up pushing or hauling the EMU (when off the wires) rather than the other way round? Since they could just work in multiple under wires? If portion working was in use like this why bother seriously overpowering the EMU just so you can turn off the DMU?

 

[dcsprior]

Isn't it the DMU that should most likely end up pushing or hauling the EMU (when off the wires) rather than the other way round? Since they could just work in multiple under wires? If portion working was in use like this why bother seriously overpowering the EMU just so you can turn off the DMU?

What I meant was a short train (the DMU) running on the unelectrified bit of the line and a longer train (DMU + EMU) on the electrified bit, without the DMU's engines running

 

[Saperstein]

The reason the 170s that Southern got hold of were re-classified as 171s was because the couplers were changed to the type used by the Electrostars so the 171s could rescue a failed 377 EMU. (Or vice versa?).

I’m not sure if this means full compatibility or just towing a dead unit or even if it’s been used?

Saperstein.

 

[gimmea50anyday]

The 210 was as I understand it built to be able to work in multiple with a 317 and 455 although there was never any real need to (combined east grinstead/uckfield train?) And I am not aware of any instance where this actually happened . Theoretically any desiro can MU as can any adtranz/bombardier *star unit although again in practice this has never been tested as the different TOCs have different coupler requirements and have made their own updates to the TMS which has likely removed any compatibility the units may have had. Only the SWML has used the powered EMU concept on Waterloo Weymouth workings as already described above but using class 33 diesel locos and trailer control MUs

A voyager has tested hauling a pendolino but this was rescue scenario as opposed to any multiple working compatibility

 

[big all]

i suppose thats exactly what a 800 unit is but better balanced

thumper 1111 when refurbished had the controller set up for four rather than the usual 7 positions and with a bit off quick rewiring could work with any 1957 [3rd rail powered] onward stock [engine off and aux power on buttons required]

but dont think it ever worked with any in anger.

 

[43096]

The 210 was as I understand it built to be able to work in multiple with a 317 and 455 although there was never any real need to (combined east grinstead/uckfield train?) And I am not aware of any instance where this actually happened . Theoretically any desiro can MU as can any adtranz/bombardier *star unit although again in practice this has never been tested as the different TOCs have different coupler requirements and have made their own updates to the TMS which has likely removed any compatibility the units may have had. Only the SWML has used the powered EMU concept on Waterloo Weymouth workings as already described above but using class 33 diesel locos and trailer control MUs

A voyager has tested hauling a pendolino but this was rescue scenario as opposed to any multiple working compatibility

The 210 couldn’t work with the 455 fleet as the latter use control jumpers rather than full auto couplers.

 

[gimmea50anyday]

Yes, of course they do! D'oh! Not sure if that made them compatible with other 3rd rail stock of the time despite having same running gear. So just 317 then (in theory, don't know if it was ever tested or proven)

 

[driver_m]

The 210 was as I understand it built to be able to work in multiple with a 317 and 455 although there was never any real need to (combined east grinstead/uckfield train?) And I am not aware of any instance where this actually happened . Theoretically any desiro can MU as can any adtranz/bombardier *star unit although again in practice this has never been tested as the different TOCs have different coupler requirements and have made their own updates to the TMS which has likely removed any compatibility the units may have had. Only the SWML has used the powered EMU concept on Waterloo Weymouth workings as already described above but using class 33 diesel locos and trailer control MUs

A voyager has tested hauling a pendolino but this was rescue scenario as opposed to any multiple working compatibility

That’s totally right. They can’t couple other than mechanically and has only happened a few times. (221/390)

 

[George109]

Could a 377 and 171 work in multiple in passenger service? (for uckfield where half of the route is electrified). I don't see why not as they have the same coupler so you could make a bimode train?

 

[aleggatta]

Could a 377 and 171 work in multiple in passenger service? (for uckfield where half of the route is electrified). I don't see why not as they have the same coupler so you could make a bimode train?

not permitted in service, one of the reasons being the 377 auxiliaries run at 110V and the 171 runs at 24V. Supposedly if you fully couple both units you get an aux voltage of 70 odd volts between the units, and I think you have to isolate some safety systens (Pass comm, Door interlock and operate the EBS) as these are fed from the rear cab, and would not have enough voltage to operate the 110V coil on the interlock circuits or the coils on the brake raft of the 377.

 

[swt_passenger]

Could a 377 and 171 work in multiple in passenger service? (for uckfield where half of the route is electrified). I don't see why not as they have the same coupler so you could make a bimode train?

The mechanical coupling compatibility is for rescue of a failed train only. AIUI from previous discussions the electrical connector block would not be engaged in such circumstances.

 

[Fincra5]

The mechanical coupling compatibility is for rescue of a failed train only. AIUI from previous discussions the electrical connector block would not be engaged in such circumstances.

Indeed the ECB would be isolated and only Air would be used, to allow the brakes off the 171 or Vice Versa.

 

[36270k]

i suppose thats exactly what a 800 unit is but better balanced

thumper 1111 when refurbished had the controller set up for four rather than the usual 7 positions and with a bit off quick rewiring could work with any 1957 [3rd rail powered] onward stock [engine off and aux power on buttons required]

but dont think it ever worked with any in anger.

The Tadpole units at Redhill had a 7 notch controller in the motor and a 4 notch controller in the ex-epb driving trailer but could still run in MU with other SR DEMU's

 

[big all]

The Tadpole units at Redhill had a 7 notch controller in the motor and a 4 notch controller in the ex-epb driving trailer but could still run in MU with other SR DEMU's

apparently if you coupled 1111 to a tadpole only 3 notches would work
i assume 1 [shunt] 3 or 4 and 7[full power ]