2 car ac emu - practical?

[6Gman]

After another journey on a very crowded 350 I wondered whether a 2 car unit was practical in engineering/electrical terms? There are quite a few 2 car dc units "south of the river" and the Clacton Units included 2 car sets at one time but would such things be practical now?

(I realise that they would be of relatively low capacity with two cabs and a disabled toilet to include, and not sure what could be done about First Class, but 6 cars between Birmingham and Liverpool and through the Trent Valley e.g. may become increasingly appropriate.)

 

[hexagon789]

After another journey on a very crowded 350 I wondered whether a 2 car unit was practical in engineering/electrical terms? There are quite a few 2 car dc units "south of the river" and the Clacton Units included 2 car sets at one time but would such things be practical now?

(I realise that they would be of relatively low capacity with two cabs and a disabled toilet to include, and not sure what could be done about First Class, but 6 cars between Birmingham and Liverpool and through the Trent Valley e.g. may become increasingly appropriate.)

It's definitely possible but I'm these days of every increasing passenger numbers I think the view is the most cars you can make fit the better. The Class 309 Clacton 2-car sets were designed to augment the other sets at peak times with greater capacity and extra power to provide resilience to the peak timetable.

I think 2-car might happen as a direct replacement for a DMU on a branch perhaps but not otherwise.

 

[swt_passenger]

I think any likely extension on single 350 operated routes would be straight to 8 car. As there’s shortly to be a surplus of 3 car EMUs anyway, can’t see anyone introducing any new 2 cars...

 

[Domh245]

The only reason you'd see 2 car EMUs are for routes like the Marlow Branch where you can't fit a 3 car train - and of course, anything is possible when you throw enough money at it. For peak time lengthening, the preferred (and sensible) solution currently is to just run a long fixed formation train and stomach the excess capacity during the off-peaks, that way you get the maximum possible capacity for a given length of train.

 

[6Gman]

On the specifics of Birmingham - Liverpool 6 coaches would need SDO at (I think) Penkridge and Winsford alone; 8 coaches would need it extensively with the consequent impact on dwell times.

 

[HSTEd]

After another journey on a very crowded 350 I wondered whether a 2 car unit was practical in engineering/electrical terms? There are quite a few 2 car dc units "south of the river" and the Clacton Units included 2 car sets at one time but would such things be practical now?

(I realise that they would be of relatively low capacity with two cabs and a disabled toilet to include, and not sure what could be done about First Class, but 6 cars between Birmingham and Liverpool and through the Trent Valley e.g. may become increasingly appropriate.)

On the Continent they have single car AC EMUs.
Given that essentially all the traction gear on a Class 319 is in a single vehicle, there seems to be no reason that EMUs cannot be built to arbitrary lengths, from one car to one thousand.

 

[Jonny]

The only reason you'd see 2 car EMUs are for routes like the Marlow Branch where you can't fit a 3 car train - and of course, anything is possible when you throw enough money at it. For peak time lengthening, the preferred (and sensible) solution currently is to just run a long fixed formation train and stomach the excess capacity during the off-peaks, that way you get the maximum possible capacity for a given length of train.

I would presume that a longer fixed-formation set with regenerative braking would have little (but still some) excess consumption over a single half-set anyway.

 

[swt_passenger]

The only reason you'd see 2 car EMUs are for routes like the Marlow Branch where you can't fit a 3 car train - and of course, anything is possible when you throw enough money at it...

It’s also generally believed that a problem like the Marlow Branch still won’t justify what would be a very small sub fleet of short units, hence wiring being cancelled.

 

[delt1c]

It's definitely possible but I'm these days of every increasing passenger numbers I think the view is the most cars you can make fit the better. The Class 309 Clacton 2-car sets were designed to augment the other sets at peak times with greater capacity and extra power to provide resilience to the peak timetable.

I think 2-car might happen as a direct replacement for a DMU on a branch perhaps but not otherwise.

2 car 309's were to operate the Walton service when the train split

 

[James James]

You wouldn't need to waste space on 2 cabs - one cab should be enough. That would however require good planning to make sure the 2-car unit is in the right place at the right time. (Swiss railways do the same thing a lot, admittedly with unpowered carriages including a DTSO at the end instead of single-ended EMU's, but it's a similar concept. That said, they do have shunters to move those extension carriages in/out the platform in the first place - I have no idea what regulations are for blind shunting in the UK.)

 

[D365]

How would you turn a two car EMU driving car around at the end of a branch line?

 

[edwin_m]

One problem with short AC units is that when coupled together the pantographs are relatively close together, and the passage of the first one disturbs the wire so the second one has poor contact. I think the pans on the two-car 309s were above one cab - were these formed and worked so it was always at the opposite end from the main unit? That might be a solution if two-car units had to couple in service although it obviously relies on keeping them the right way round and having them arrive at the coupling location in the right order. The other option would be to restrict the speed of the coupled for mation.

I suspect if a line only justifies a two-car unit on its own and no coupling is involved, then it probably doesn't have enough passengers to justify electrification.

 

[HSTEd]

I suspect if a line only justifies a two-car unit on its own and no coupling is involved, then it probably doesn't have enough passengers to justify electrification.

Well that depends upon the timetable I imagine.
Although the Network Effect has been hurt badly by the invention of practical 25kV bi-modes, you could imagine a situation where a line that carries long distance trains might need two car trains for local services.

 

[D365]

Although the Network Effect has been hurt badly by the invention of practical 25kV bi-modes, you could imagine a situation where a line that carries long distance trains might need two car trains for local services.

How much more would it cost to run a hand-me-down 321 compared to a new build 2 car? Both would be considered "microfleets" in this instance.

 

[PeterC]

2 car 309's were to operate the Walton service when the train split

Sorry, as originally formed the Walton portion was the 4 car without buffet, the other 6 cars worked to Clacton. The 2 car units were later extended to 4.

I see no logical reason why units cannot be designed so that they can be easily reformed with 2 driving cars and zero to many intermediate cars. The killer is the requirement for disabled toilets and wheelchair spaces which would take up a disproportionate amount of space in a short unit.

 

[HSTEd]

How much more would it cost to run a hand-me-down 321 compared to a new build 2 car? Both would be considered "microfleets" in this instance.

Well in the long time horizon, the Class 321 will inevitably succumb to corrosion damage so the new unit is the only option.

 

[D365]

I see no logical reason why units cannot be designed so that they can be easily reformed with 2 driving cars and zero to many intermediate cars. The killer is the requirement for disabled toilets and wheelchair spaces which would take up a disproportionate amount of space in a short unit.

Hold on, that sounds familiar...

[Photo: FGW HST in "2+1" formation at Dawlish on an ECS move.]

 

[D365]

Well in the long time horizon, the Class 321 will inevitably succumb to corrosion damage so the new unit is the only option.

The 321 was an example as there'll be the Renatus units available. There's plenty of post-privatisation AC EMUs that could be "handed down" in the future.

 

[Elecman]

Would a branchline unit actually need a toilet?

 

[DanNCL]

Modern 2 car AC EMUs are used on the continent. I can't see any reason why it wouldn't be possible to have 2 car AC EMUs in the UK, although it's unlikely that any would be built for the UK.

Bombardier manufacture a 2 car version of their Talent 2 family on the continent. In theory they could do the same with the Aventra in the UK.

 

[sd0733]

I believe that the new Aventra trains have longer coaches than a 350 so when the new 5 cars enter service they will essentially be comparable to a 6-car 350 anyway therefore filling the niche in the OP with no issues.

 

[WatcherZero]

Would a branchline unit actually need a toilet?

Depends on journey length, there is supposed to be loos on routes longer than an hour and some rural unstaffed stations wont have toilets.

 

[swt_passenger]

Depends on journey length, there is supposed to be loos on routes longer than an hour...

There’s no such rule. We’ve covered this often.

 

[PeterC]

Hold on, that sounds familiar...

[Photo: FGW HST in "2+1" formation at Dawlish on an ECS move.]

Exactly

 

[dubscottie]

We have managed with 2 car (DC) overhead EMUs without bogs here in Dublin for years.

The original DART units. 2/4/6/8 car trains. We have 5 x 2 car Alstolm units going spare. Should be easy to convert to AC and should fit the GW loading gauge!

 

[WatcherZero]

There’s no such rule. We’ve covered this often.

An hour has been the previous guidance.

Current guidance from the ATOC Key Train Requirements V4 2016

3.10.1 Whilst the provision of toilets on trains is now very much the accepted norm, it should not be automatically assumed that this is appropriate for all types of train operating all types of duty cycle. As an example, passenger capacity on metro is frequently a critical factor in train design and the installation of toilets inevitably occupies a significant amount of space. It is therefore common practice worldwide not to provide toilets where this type of train is operating intensive services with frequent stops into and across large conurbations. It is therefore recommended that, when considering the provision of toilets, consideration is given to typical journey times and to the potential availability of toilets at stations and other locations nearby.

There is also guidance on toilet ratio, 1 per 85 passengers on Long Distance and Outer suburban, 1 per 125 passengers on Commuter and inner Suburban. This European standard replaces the earlier British guidance that there should be 2+1 disabled for the first 4 carriages then an extra toilet for every odd carriage.

 

[theageofthetra]

Does anyone know if the 466's will have the DDA compliant toilet mod done? -can only think of two routes they are used on as a lone unit and they would ideally have a 465 on if possible.

 

[class387]

Does anyone know if the 466's will have the DDA compliant toilet mod done? -can only think of two routes they are used on as a lone unit and they would ideally have a 465 on if possible.

I was wondering this too, given that both those routes are very short.

 

[driver_m]

Liverpool - Bank Quay services would usually be ideal for a 2 car AC unit if such a unit could be brought in. Also be handy for some infills like Morecambe, chester or otmskirk on the WC but obviously that's getting into spending money territory and that won't do!!

 

[Alteran Ancient]

Does anyone know if the 466's will have the DDA compliant toilet mod done? -can only think of two routes they are used on as a lone unit and they would ideally have a 465 on if possible.

There's nothing to say they couldn't do this, but it has been suggested that they probably won't. By themselves, the 466s aren't DDA compliant. The only place they have regular usage is to strengthen additional services (which would be DDA compliant on journeys longer than 60 minutes), used by themselves on the Bromley North popper (a total journey time of about 5 minutes) or the Sheerness line (less than 20 minutes).

The 466s may now well have a limited future with Southeastern - I would expect the networkers to be replaced with something more suited to Metro workings come the next franchise. Personally, I think they're reasonable units - I'd certainly take them over a pacer any day of the week, but given they're probably beyond conversion to AC, will likely not find a new home.