[PR] DART Battery Train Tender Issued

[James Shields]

Originally Posted by Mark Gleeson

BUT here is the stinker you cannot charge while stationary as the overhead wire would melt if you pulled more than about 150amps while stationary. Under full power each 2 coach pulls 500amps so to charge you would need to be able to support much higher currents

The ideal would be to draw enough power to charge the batteries while in motion. If you need 500amps to drive the train, what's required to draw another 200amps for charging? I'm sure trains in other countries draw much more power than the DART. Are we at the limit of what can be done at 1500V?

The ideal situation would be have a train run Connolly to Bray on overhead power, and arrive back in Connolly (or wherever the overhead lines have got to) with fully charged batteries, ready to head out into the unpowered section.

Also, would it make sense to start electrification from the Maynooth and Hazlehatch ends, so the gap is in the middle rather than at the ends?

[James Howard]

I think the issue is that the cable will overheat at the point where it connects with the pantograph if the train is stationary and drawing a lot of current. If the train is in motion, the connection point is in effectively in motion and so the resistive heating is only happening in the one spot for a short amount of time.

This battery idea strikes me as being a bit of a greenwash. At face value, the original idea of bi-mode makes a lot more sense if it's a contingency for delays in electrification. If the electrification is a couple of years late, they'll be ripping out a relatively cheap engine with a year or two to go before overhaul rather than a vastly expensive battery with a decade or more life left in it.

Still, at least the 50km range removes the temptation to run high-density commuter units to Sligo.

[ACustomer]

I know this sounds a bit nostalgic, but over 80 years ago Prof Drumm's patent battery trains were effectively doing 50km on a full charge. So what's with all this fancy new lithium battery technology?

Also as far as I am aware the Drumm trains used to recharge from a fixed point at Amiens Street, using a pantograph..

The more I think about it the more I fear that bi-modal battery trains will be an excuse for not providing a more comprehensive proper electrification.

Also we should not get advice from the UK on electrification projects. They have a cost over-run history worth of the HSE. So for advice go the Spaniards, the Portuguese, the French, or others who have done electrification on fairly lightly trafficked lines which does not appear to cost the earth.

[Mark Gleeson]

We have to look at the long term sustainability. Irish Rail is hemorrhaging money due to the need to run these 'thin' commuter routes.

So there needs to be a coherent policy which clearly states there will be no increase in service levels. Set out a service pattern and stick to it. You might be able to justify a train out to Mullingar after 9pm but its sketchy.


The whole battery thing is a stop gap, the trains are the longest lead item, no one wants a fleet of trains you cannot use, equally no one wants wires with no trains.

The charging is a problem that needs to be worked out, a train draws power when stationary, the lights, heating, AC are all heavy electricity users which uses up a considerable amount of the power budget

You cannot really charge while accelerating to to do so would result in trips on the substation at peak hours. You can charge while coasting and braking and a marginal amount while stationary. There is a huge impact on the existing infrastructure which is not scoped with this use in mind.

A railway works order is in preparation for the Maynooth line and thats mainly about the level crossings and other supporting works. Irish Rail doesn't want to get into resignaling and electrification until the solution to close all the level crossings is agreed as this has a huge impact on the signaling design and also the overhead wires design.

That said you could electrify M3 Parkway/Maynooth to Clonsilla tomorrow without need for any permissions, equally electification out as far as beyond Broombridge looks sensible until you consider the possible works needed at Glasnevin Junc to increase capacity and also the new station to link to Metro.