Prototype B5 bogie (MK1s & MK2s), what's the generator for?

Discussion in 'Coaching stock' started by tomstaf, 6 May 2014.

  1. tomstaf

    tomstaf Western Thunderer


    My tape measure was roaming yesterday and I found these generators attached to the inner end of B5 bogies under TPO stock.
    MK1 B5 BOGIE 1 2014_0505FS.jpg MK1 B5 BOGIE 2 2014_0505FS.jpg
    Anyone know what they're for, and are they just on TPOs or do all B5 bogies have them?


  2. Heather Kay

    Heather Kay Western Thunderer

    I believe these replace the traditional dynamo. It was an idea introduced on the XP64 stock, and as far as I can tell all new Mk2 stock used this system from new. Mk1s that received B4 bogies continued to use the original dynamo.
    tomstaf likes this.
  3. tomstaf

    tomstaf Western Thunderer

    Thanks Heather. Looks like I've got some etched ends to start drawing then...


  4. Heather Kay

    Heather Kay Western Thunderer

    I think the uprated Mk1s B4 bogies still had the brackets, or at least the fittings for the bracket and dynamo proper. It's worth peering at photos.
  5. OzzyO

    OzzyO Western Thunderer

    It just looks a better way of mounting the dynamo, but it could also have come about because of using Vee belts to drive the dynamo.
    A flat belt will allow some movement from a straight line. If you do this with a Vee belt it will rub and wear the sides of the belt.

  6. Ian G

    Ian G Western Thunderer

    I have a few photos arfound a pair of B4's taken some time ago at the Bucks railway centre

    Ian G
  7. Bob Reid

    Bob Reid Western Thunderer

    B4/B5's on Mk1's with conventional dynamo's had a different (dropped) headstock to clear the dynamo belt - only the Mk2's and the Mk1 Postals (conversions and retrofitted with Alternators) and Mk2's with Stones (or CAV)? Alternators used the headstock bracket. The biggest advantage (apart from the rather more up to date electrical system) was the ability to run at high speed without regularly throwing dynamo belts - a perennial problem with the underframe mounted dynamo and the single flat drive belt.
    Pugsley and tomstaf like this.
  8. Heather Kay

    Heather Kay Western Thunderer

    Bob, what would we do without you?

    I love this forum!
  9. tomstaf

    tomstaf Western Thunderer

    Thanks Bob,

    Am I right in thinking it is just the B5s that had the bogie mounted dynamo?


  10. Bob Reid

    Bob Reid Western Thunderer

    the only B5's I've found with the bogie mounted alternator were some TPO's (two Alternator's - one on each bogie) and the B4 fitted Mk2's up to and including Mk2c.