-
Our new ticketing site is now live! Using either this or the original site (both powered by TrainSplit) helps support the running of the forum with every ticket purchase! Find out more and ask any questions/give us feedback in this thread!
Performance of battery EMU under OHLE vs. when drawing from battery
- Thread starter eldomtom2
- Start date
- Status
Sponsor Post - registered members do not see these adverts; click here to register, or click here to log in
R
RailUK Forums
Fincra5
Established Member
- Joined
- 6 Jun 2009
- Messages
- 2,636
Do we even have any that do?
But I believe when the 379 was used as a Batt/AC trail unit, there was a big difference in performance yes...
AC is at 25kv, so there's more on tap!
But I believe when the 379 was used as a Batt/AC trail unit, there was a big difference in performance yes...
AC is at 25kv, so there's more on tap!
What about e.g. the Merseyrail units? Is there a difference between them running on third rail and them running on batteries?
Fincra5
Established Member
- Joined
- 6 Jun 2009
- Messages
- 2,636
Well according to Wikipedia: For the Class 777 -
| Maximum speed |
|
|---|
So from that, it looks like performance is less than on the juice. Although acceleration seems to stay the same... I guess a Merseyrail Driver would be best placed to answer.
stevieinselby
Established Member
There may be a difference between available power and rationed power – drivers giving it the beans might be able to achieve the same power when running off battery or external power, but if doing that drains the battery too quickly then it will be rationed in service. Given the nature of the service, I would expect the priority to be on maximising acceleration over outright top speed – especially as little if any of the Merseyrail network has a linespeed of more than 60mph, so there's little benefit to allowing trains to run faster.
The class 777 were specified with batteries to allow a certain performance capability.
The Stapler Flirt AKKU in Germany have performance on battery power or OHLE which is very similar whichever source is used. Sorry unable to post a source due to being covered by NDA's but if I find an open source document I'll edit to post a link.
The Stapler Flirt AKKU in Germany have performance on battery power or OHLE which is very similar whichever source is used. Sorry unable to post a source due to being covered by NDA's but if I find an open source document I'll edit to post a link.
306024
Established Member
The 379 could keep time (just) on the Harwich branch trials, but the line speed is only 60mph with stops to test acceleration. Performance beyond that would perhaps have been a struggle.
In essence this question is all down to the specification of the batteries concerned.
A BEMU can have varying performance in battery mode depending on the battery performance specified.
For an BEMU operating mainly on the juice like the class 777 a lower specification battery is likely to be provided. If you're expecting a BEMU to operate predominantly off the OHLE as in Holstein in Germany then the batteries specified will allow a performance on battery very similar to on OHLE.
In a nutshell it depends on the benefit to cost ratio of higher spec batteries versus journey times.
edwin_m
Veteran Member
Space and weight will also be a consideration. The Continental loading gauge leaves more room for batteries on the roof, but the British one is more restrictive and the 777 has lower floors too. If they can't be fitted above or below, they will reduce the passenger space. And more batteries make the train heavier, reducing performance and increasing power consumption, though this isn't a particularly big part of the total train weight.
- Status