Should we be building new dual voltage units?

[pemma]

Ignoring the Thameslink and Crossrail orders, should other orders for dual voltage be going ahead considering we have 350/1s with redundant 3rd rail equipment and are set to have 319s with redundant 3rd rail equipment.

Would new OHE only make more sense leaving 350/1s and 319s to replace the likes of the 313s and provide extra capacity on non-Thameslink and Crossrail routes?

 

[gordonthemoron]

why would crossrail be dual voltage?

 

[mallard]

I think we should make sure all future orders are as flexible as possible. 3rd-rail capacity comes at very little cost to OHLE-capable units and all current and future 3rd-rail vehicles at least have the capacity to be converted to OHLE, particularly with recent comments that 3rd-rail "has no future" (which I think is a little overblown, it has its place).

 

[pemma]

why would crossrail be dual voltage?

I wasn't sure if they'd need to be so I left them in as an exception.
--- old post above --- --- new post below ---

I think we should make sure all future orders are as flexible as possible. 3rd-rail capacity comes at very little cost to OHLE-capable units and all current and future 3rd-rail vehicles at least have the capacity to be converted to OHLE, particularly with recent comments that 3rd-rail "has no future" (which I think is a little overblown, it has its place).

By all means order new 3rd rail only units as and when required. However, as there will be many dual voltage units using AC only, should we order new dual voltage units or should we ordering new AC only units and cascading the dual voltage units to utilise both currents?

 

[jopsuk]

Pretty sure Crossrail is being specified as AC-only. This leads to issues should they wish to extend beyond Abbey Wood, as the line would have to be dual-electrified. Not impossible, just expensive and tricky over long stretches.

 

[swt_passenger]

A new AC unit will always be easily DC convertible (by adding shoe gear) because the nature of modern traction design is that there is a reversible DC link between the transformer and the traction converter.

A new DC unit will also always be AC convertible because space will be left for retrofitting a transformer and a roof well will be provided for a pantograph.

I'd just think of them as flexible EMUs that can run on either or both depending where they are first ordered for. Easy conversion automatically results from the variable voltage and frequency (VVVF) AC traction technology used.


--- old post above --- --- new post below ---

Pretty sure Crossrail is being specified as AC-only. This leads to issues should they wish to extend beyond Abbey Wood, as the line would have to be dual-electrified. Not impossible, just expensive and tricky over long stretches.

Definitely AC only. There was a rumour going round a year or two back that the Connaught tunnels couldn't or wouldn't be wired - possibly for cost saving, and they'd be using DC on the SE leg of the route, so I emailed them about it. One of their electrification team replied that it was pure speculation, and they were always taking AC to Abbey Wood.

 

[ChrisCooper]

They will be AC only, but like any other modern stock there will be nothing stopping them being converted to DC in the future.

I don't know of what orders for "dual voltage" stock there are going to be anyway, beyond the Thameslink stock and any more for London Overground. Merseyrail may go for dual voltage stock, but 319s aren't suitable for that anyway, plus they want new stock, not slightly newer stock. The only other potential DV order in future is in relation to link up between the GW electrification and the SR electrified network, but by the time that is needed the 319s will be getting on even more and already allocate (even more stupid would be to order new AC only trains and store the 319s until a future time when more DV units may be needed).

It has to be remembered that all stock since privatisation has been dual voltage, even if not fitted with all the equipment. As has been said, modern electronics makes it easy. Ordering stock as AC only has no real advantage, you only really save on the lack of shoe gear, but most "dual voltage" stock doesn't have that anyway.

Are the 350/1s actually fitted with shoe gear anyway? I thought it was removed after they finished on the Brighton-MKC service?

 

[swt_passenger]

Are the 350/1s actually fitted with shoe gear anyway? I thought it was removed after they finished on the Brighton-MKC service?

Very difficult to tell just by looking. With the shoe arm in the raised position it isn't really visible even from an adjacent platform. I took the attached picture at Milton Keynes during the loan to SN...

 

[Class377/5]

The 350/1 have had their 3rd rail gear removed since they returned to LM. It can be re-instated easily if the future needs arises.

Crossrail stock is AC only but should have the ability to be converted easily (read cheap) in the future if they do go beyond Abbey Wood.

 

[pemma]

Very difficult to tell just by looking. With the shoe arm in the raised position it isn't really visible even from an adjacent platform. I took the attached picture at Milton Keynes during the loan to SN...

I've never seen the name of the operator alongside the destination on a train before, even on a 350 before LM days when some services changed operator at Rugby.

 

[MCR247]

I think it was just so pax didn't think it was a LM service