View Single Post
  #26   Report Post  
Old January 17th 08, 10:44 PM posted to uk.transport.london, uk.railway
D7666 D7666 is offline
external usenet poster
 
First recorded activity at LondonBanter: Jul 2003
Posts: 529
Default North London Line AC/DC question

various snipped out

I don't know what the current limit relays were set at on 501s but
being 4 motors per unit would be likely to draw more than a two motor
2EPB.

Published ''spotting book'' values of a 2EPB are 2x250 hp and 501
4x185 hp so that makes a 501 in round figures 50% more powerful than a
2EPB - but I'd caution those numbers with similar comments I have made
before about DC EMU in that the current limit relay setting needs to
be known to understand peak current draw.

As regards another part of the thread, I thought 2x313 operation was
killed by platform length limits. 501 units were on 57 foot frames
and platforms that could take 6cars laid out for that length - but
could not take standard 6car sliding door trains with 20 m bodies.

And I can't see why a 6car 313 would draw siginficantly more power
than a 6car 501 to trip traction supplies. Again using ''spotting
book'' values, without current limit values, a 313 has 8x82 kW motors
that in round figures is 880 hp per unit - while a 501 is 740 hp.

I would have expected the LNWR DC supply to have been a bit more
robust than that as the overall load increase taking all traffic is
not 20% from a simple 313 and 501 comparison - but is Bakerloo+501
c.f. Bakerloo+313 with the Bakerloo load unchanged.

Must admit never thought about this aspect before, I might be wrong,
its not a route thats easy to obtain gen on the traction supplies.

--
Nick