3rd Rail Pan Wells

[TheEdge]

As per the title, why were so many post privatisation 3rd rail units built with pan wells?

Was there an expectation of OHL on third rail territory or is it something else? And do similar age OHL units have the parts in place to convert to 3rd rail?

 

[Harbouring]

I guess it is more to do with being able to move a 3rd rail train to another operator that has OHLE operation or possibly to allow it run through from 3rd rail to OHLE such as Thameslink or southern to MK

 

[cj_1985]

ISTR that some of the SE 375's were ordered with pantographs as, originally, Connex wanted to use some of the 375s on CTRL/HS1.... Without checking, I that would be the 375/6s. The rest... is largely down to the likes of the Desiros and Electrostars (I think some of the Junipers were also built like this) being modular. As has been said above, this would allow the operator, or ROSCO, to re-equip the units with the kit needed to operate away from OHLE onto 3rd Rail.... or vice versa

 

[swt_passenger]

AIUI all post privatisation units have three phase AC traction, and most 'southern' DC units (such as 37x, 450 and 444) are capable of conversion to AC or dual voltage in their as built condition. I believe DfT have insisted on this capability for some years.

Their is very little hardware to add to AC units of similar vintage to allow them to run on DC, because they almost invariably have a DC link between their pan/transformer and the traction converters. In simple terms it is shoe gear, connecting cabling, and fuses/breakers.

Apart from the outliers such as those Junipers that don't have existing pan wells, I don't believe either AC to dual, or DC to dual, is a technical issue. Just needs the money...

 

[Bald Rick]

It's not a DfT requirement, as with a couple of recent exceptions, they don't specify or buy the trains.

It is a requirement of the people who buy the trains, ie the leasing companies. The concept is residual value.

If you are spending upwards of £5m on an asset (a train), but only have security of income from that assets for the length of a franchise (7-10 years), you want to make sure it has the widest possible future use at the end of the lease period. Whilst it is likely that the train will find continued use with the successor franchise, this is by no means certain. See class 707.

Therefore, if you specify a train designed for DC traction with a pantograph well and a few other bits necessary for conversion to AC traction (space and mounting points for the main transformer, cable runs, space for equipment boxes) you will get that at practically no cost. Indeed if the factory is already making similar AC trains they can use the same design and manufacturing jigs, which actually makes it potentially cheaper. Then if the lease runs out, and the new franchisee doesn't want the trains (see class 707), it is a much cheaper job to convert them to AC than to start cutting holes in welded aluminium bodyshells, and shifting kit around underneath the train.

This means that the chances of finding a future user for the train is higher, which makes the future value (residual value) of the train is higher, which in turn means that the leasing company can then take the risk of lower lease charges for the train when new, as it will be more likely to make money on it in later life.

 

[swt_passenger]

It's not a DfT requirement, as with a couple of recent exceptions, they don't specify or buy the trains.

It is a requirement of the people who buy the trains, ie the leasing companies.

That does makes more sense. Perhaps I read it in some ATOC thing or other about future fleet issues, however your explanation suggests it has become a de facto industry standard. Should reassure the OP that it is a good idea anyway...

 

[Skie]

The new Merseyrail units will have pan wells and space for conversion kit, and they arent even being bought by a ROSCO. I think it's just a common sense option. Get the work done during the build and it's likely the cost will be minimal, but if you have to do the major work mid-life then the costs and disruption will be considerable.

 

[edwin_m]

As discussed on various forums here, many possible extensions of Merseyrail could see them running under 25kV overhead, so making provision for that system is a good idea even if the units spend their entire life on Merseyrail.

Conversely, the Crossrail units have provision for third rail because of possible extension from Abbey Wood towards Dartford.