Battery electric multiple units

Can battery-electric multiple unit trains offer a practical alternative to electrification in a commuter rail or regional rail context?

Given that Tesla claims a range of over 200 miles for its electric automobiles, what would the practical range be for a battery-powered EMU?

The local commuter rail system in my area relies on diesel-hauled trains, and the one that brought me home last night consisted of a locomotive and six cars, only one of which was occupied. Moving empty cars back and forth on off-peak runs is surely a waste of energy, and must more than negate any energy savings from riding the train versus driving an automobile. But switching cars in and out of a locomotive-hauled train to respond to changing demand cannot be practical, so it is natural to wonder if a battery-powered EMU might be the answer.

Has any research been done on the subject?

Germans did it decades ago , can it be done yes, does it save energy or pollution, probably not .
after all a KiloWatt is a Kilowatt, be it generated at a power plant or a local diesel.

https://www.google.com/search?q=german+ ... BB4wNB13_M" onclick="window.open(this.href);return false;:

Several American companies even had battery cars a century ago, like the LIRR for instance. Never many and not for any length of time after diesel power became the standard, but they’ve been here.

Tesla (the company) could license its batteries to another company, I suppose. The problem remains that batteries take ages to charge fully - that’s one area where Tesla has technology that could make battery-electric rail much more feasible.

One of the new DMU FLIRTs being built by Stadler for Arrow will have batteries installed in the power car vs diesels, funding by the State of California mostly as a test vehicle. The Arrow line will only be 9 miles in length, not the hundred of miles you're wishing for.
https://en.wikipedia.org/wiki/Arrow_(commuter_rail_line" onclick="window.open(this.href);return false;)

The Wiki rolling stock paragraphs reflect upon the decisions made over what type of train to use.
The locals preferred light rail, but the projected construction costs was too high to fall under the FTA "Small Starts" funding program - and had too small projected ridership to fall in FTA "New Starts" funding program. The decision was made to go with conventional commuter rail using retiring Metrolink cars to lower construction costs meet the FTA "Small Starts" funding program. But the locals did not want double decker railcars and huge locomotives pushing and pulling trains within their communities. So the end result is the lighter weight, single level, Stadler FLIRT DMUs - 3 with diesel power cars and 1 with Li-Ion batteries.

Of the 9 miles of track, 2 miles in the middle will be double track so trains can meet each other at speed. There will be catenaries over some of the track, I'm not sure how much or where, to charge the batteries in the sole Li-Ion battery EMU.

It will be interesting to see how well that FLIRT performs.

The Electric Power Research Institute ("EPRI") is the leading research agency for research and development of new electrical power supply, delivery, uses and technology. At least 15 years ago I attended a couple of meetings where EPRI presented a proposal for capacitive coupling high rate enroute charging for lightrail vehicles for areas where passenger traffic density was insufficient to economically build catenary. The gist of the proposal was that a large capacitor plate would be installed under each vehicle and a matching plate between the rails at each station stop. The track would form the electrical return path. The high rate battery charging would occur during the period each vehicle was stopped at station platforms for passengers to get on or off. More recently the potential to use supercapacitors in lieu of or in concert with batteries has been discussed. The EPRI site has extensive indexing and some of its products are available at no cost to non-members. For example: https://www.epri.com/#/portfolio/2019/p ... lang=en-US

I think I read awhile back that that system was being installed somewhere in Germany, but I can't remember the city--Mannheim? Anybody know whether that was done and how it's working?

Thomas Edison built a battery EMU, it ran on LIRR. He also custom-built nickel-iron batteries for it, a type very well suited to railroads. It an a pretty good distance, I believe.

railroads with tunnels like Amtrak, lirr and metro north are very leery of gas and explosion issues .
I brought up the battery powered switchers/gen set units and they just about told me to quit.
despite NYCRR tri power units , the railroad did not want them.

Triaxle wrote:Thomas Edison built a battery EMU, it ran on LIRR. He also custom-built nickel-iron batteries for it, a type very well suited to railroads. It an a pretty good distance, I believe.

Yep, that’s the type of railcar I reference above - it seems to have not been uncommon, especially for moderately-slow service a few times a day (since charging them took a long time.) New Zealand used some Edison-Beach railcars in regular service pretty late into the 20th century too. NiFe batteries are nice because of how tolerant they are to voltage spikes and overcharging, and how non-toxic they are, but unless I’m mistaken they don’t have a high energy density to weight (or size) ratio.

Lithium batteries seem to be the equivalent of gasoline where a Tesla-sized amount would cause a major fire but an ALP-46-sized number of batteries would be a literal bomb, so I understand why FDNY is hesitant about them in confined places. I’d love to see a safer alternative, one where manufacturers could trade a lower energy density for much more safety and lower toxicity. Nickel-metal-hydride maybe? Rechargeable alkaline? Safer lead-acid glass mat batteries? Molten sulfur?

The thing about rails is the low rolling-resistance and flat track grades mean they can use large & heavy (i.e. cheap & less toxic) batteries in trolley, subway or Commuter Rail service without paying a large penalty.

Batteries would be great in electrification projects where you have bridges you don't want to raise