Why were trains with tungsten lighting still built so late on?

Discussion in 'Railway History & Nostalgia' started by AY1975, 11 Sep 2019.

  1. AY1975

    AY1975 Member

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    Following on from the thread on why slam-door trains were still built so late on at https://www.railforums.co.uk/threads/why-were-slam-door-trains-still-built-so-late-on.172064/, does anyone know why BR continued to build trains with tungsten interior lighting for so long after it had started to build some trains with fluorescent lighting?

    For example, loco-hauled Mark 1s started to be built with fluorescent lighting from about 1959 onwards, albeit only in saloon coaches, and some DMUs and EMUs such as the Class 123s, 124s and 309s were built with fluorescent lighting in the saloons (not in the compartments, though). On the other hand, Southern Region 4-CIGs and 4-VEPs were still being built with tungsten lighting into the early 1970s!
     
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  3. randyrippley

    randyrippley Established Member

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    Will fluorescent lights work with DC power?
     
  4. Richard Scott

    Richard Scott Member

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    No, need an inverter but sure that technology was around as coach lighting runs off DC from batteries.
     
  5. satisnek

    satisnek Member

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    It was only the SR units which were the last bastion of tungsten lighting though, wasn't it? Presumably cost/simplicity/familiarity...?
     
  6. AndrewE

    AndrewE Established Member

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    Incandescent (filament) bulbs are robust, especially heavy-duty ones with thicker filaments and last even longer if run below their official voltage. I don't know whether fluorescent tubes were available in "tractionised" versions...
    When did solid state inverters come in? Lots of BR standard stock had motor-alternator sets for generating AC.
     
  7. Journeyman

    Journeyman Established Member

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    I think it was just the sheer number of tungsten-lit vehicles already in existence that led the Southern to continue using this form of lighting so late on. Lighting operated at 70v on the SR, which I think was unique, so bulbs were manufactured specially in large quantities.
     
  8. DerekC

    DerekC Member

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    I was trying to remember when solid-state inverters came in. I think power transistors were widely available in the mid 1960s, which made an
    inverter using a simple transistor oscillator driving a step-up transformer feasible. They wouldn't have been very efficient and probably produced lots of harmonics but probably nobody cared too much.
     
  9. Bletchleyite

    Bletchleyite Veteran Member

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    Maybe a slight aside, but the last trains with tungsten lighting were built in the early 2000s - the Pendolinos had tungsten halogens in both the central row of spots and the reading lamps. These have now been replaced with LEDs. However, XC Voyagers and I think 222s still have tungsten halogens in those fittings.
     
  10. Taunton

    Taunton Established Member

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    I think that until the 4-CIG etc came along, lighting was at full 750v (lights were daisy-chained so the bulbs were in series), so very simplistic switchgear. And I have to say that blacked out saloons of the Mk 2/3 type were far less prevalent on older stock.

    I regret to report inadvertently smashing a protruding tungsten bulb in a 4-CEP (pre-rebuild) one morning at Charing Cross, swinging a bag up with great aplomb onto the rack in a heroic curving movement, to impress a girl. We were off to Paris for a weekend, hovercraft from Dover, and it had rather got to me! But why did the designer put them so close to the racks. Someone told me that because of the full voltage it needed a proper CMEE fitter to change the bulbs in those.
     
  11. big all

    big all On Moderation

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    Motor alternators started with 1951 stock: EPBs, HAPs and Kent Coasters; before that all circuits were line voltage, apart from control circuits, which were reduced to 70volts by a Potentiometer (on SUBs, at least).
     
    Last edited by a moderator: 15 Sep 2019
  12. yorksrob

    yorksrob Veteran Member

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    Surely the real question should be why they ever switched from lovely, gentle, warm tungsten lighting, to hideous, glaring flourescent tubes in the first place.
     
  13. Bletchleyite

    Bletchleyite Veteran Member

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    It was the trend in the 80s. What I really don't get is why now LEDs can create a lovely warm and cosy feel TOCs insist on specifying stark bright white.
     
  14. yorksrob

    yorksrob Veteran Member

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    True on both counts. I'm sure they can even get better coloured flourescent tubes than some of the ones they use.

    Travelling at night in a tungsten lit carriage is a pleasure.
     
  15. Bletchleyite

    Bletchleyite Veteran Member

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    I also find that true of a Pendolino because of the thin warm white tubes and warm white spots. Nice and cosy.
     
  16. yorksrob

    yorksrob Veteran Member

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    158's used to have quite nice subdued lighting as well.
     
  17. PaxVobiscum

    PaxVobiscum Established Member

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    I’m not acquainted with this technology - does it use ground wheat as a coating on the glass tubes rather than one of the usual phosphor compounds? ;)

    I’m just being silly.
     
  18. Bletchleyite

    Bletchleyite Veteran Member

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    They mostly still do but it's not as classy :)
     
  19. DerekC

    DerekC Member

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    As I am sure you know really, fluorescents deliver a lot more light per kW. LEDs even better.
     
  20. yorksrob

    yorksrob Veteran Member

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    Yes, and provide all the relaxing ambience of an operating theatre.
     
  21. Bletchleyite

    Bletchleyite Veteran Member

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    LEDs can provide whatever ambiance you want, just not if you buy cheap rubbish.
     
  22. yorksrob

    yorksrob Veteran Member

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    Yes, LED's have got much better in recent years.
     
  23. Bletchleyite

    Bletchleyite Veteran Member

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    My whole house is 3-spot GU10 fittings with Philips LED bulbs and you can't tell they aren't tungsten halogen without actually looking at the bulbs.
     
  24. AY1975

    AY1975 Member

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    Yes, and I would guess that by that time, with vandalism, anti-social behaviour and violent crime on the increase, a lot of passengers felt safer in a more brightly lit environment.
     
  25. Bletchleyite

    Bletchleyite Veteran Member

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    Many still take that view now. There's as many people who call the Pendolino "cosy and subdued" as call it "dull and dowdy" or even "shadowy".
     

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