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Post by tubeprune on Sept 8, 2008 13:39:04 GMT
I'm old enough to remember train starting bells located on platforms near the driver's cab. The Met. used an "S" light, some of which are still in place. Now, my question is related to how these bells worked on the District. They were electrically operated from at least the late 1920s. You (the guard) touched the two wires suspended over the platform with the brass tip of your green flag and this made a circuit which rang the bell at the cab end and the driver would start the train. The LT museum photo collection shows some earlier photos which seem to suggest that the bell was mechanical and you had to pull down on the wire to get the bell to ring. Photo: www.ltmcollection.org/photos/results/results.html?IXsearch=U2422&button=GO! Does anyone know if this was the case and when the change from manual to electric took place? *thinks* "Station closed and trains non-stopping due to starting bell wire broken" *returns to non-thinking mode* |
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mrfs42
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Post by mrfs42 on Sept 8, 2008 16:50:46 GMT
I'd think that the bells were still electrically operated; however rather than a direct action bell (touch flag, make contact, bell rings - take flag off bell stops) I'd put a strong suggestion in that the picture in question works a 'Hustler' horn or a bell that is switched by the catenary wire - that is electrically dead. Direct action bells would have 'live catenary'.
Guard pulls wire to initiate bell, switch at bell changes state from 'off' to 'on' - bell starts ringing. Guard lets go of wire. Relay coil in series with bell. Relay picks up when bell rings, front contact of relay closes making a 'stick' circuit (bridging out bell starting contact) that is broken by train either dropping the track or platform starter dropping. I'd go for the stick circuit rather than the then relatively expensive thermal time relays - though of course a train that is stationary in the platform would have a continuously ringing bell - so there'd be a cut out that simulates the train dropping the feed to the stick circuit.
Why were these used? I'd suggest a mixture of two reasons - differing train lengths (although the 'live' catenary was positioned for about 2 car lengths of variance) or stations that were regularly non-stopped and could used the cheaper version of 'dead' catenary.
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Post by ruislip on Sept 8, 2008 22:50:41 GMT
TP, in the book Going Green on page 50, is that another example of starting bells?
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mrfs42
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Post by mrfs42 on Sept 8, 2008 23:56:24 GMT
TP, in the book Going Green on page 50, is that another example of starting bells? That's the 'live' catenary version - but; yes, that's the flag making contact between the two wires to start the train. |
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Post by tubeprune on Sept 9, 2008 6:16:55 GMT
mrfs42 - Thanks for your thoughts. I have no recollection of the bells being anything more than a single stroke, but that may be my memory failing. I thought that the earlier version was simply replicating the car to car single stroke bell system used when they had a man on every car.
ruislip - yes, this is the later version.
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mrfs42
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Post by mrfs42 on Sept 9, 2008 16:50:52 GMT
Possibly - however I've always understood them to be some form of trembler bell. Perhaps the original installations are forever lost in the mist of time.
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Post by mrfs42 on Oct 14, 2008 15:19:36 GMT
After digging around the depths of my filing cabinet, searching for clues on something completely different, I found this Train Starting Bells, although the source text appears to be an LMS publication after the formation of the LPTB; the bottom entry and footnote on page 22 is germane, covering the LMS service to Willesden from Earls Court. From the wording, I still lean towards thinking that the bell is a trembling bell - note too that on the New Lines, as on the Met. the 'S' indication light is used. A clue as to the date of the publication is contained in: '[...] In the event of a LMS electric train failing from any cause between Gunnersbury an Richmond it may be propelled or drawn by a LPTB train of the new wide pattern stock, by means of the coupling chains provided for the purpose, and kept at Gunnersbury, Kew Gardens and Richmond. [...]' |
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Post by Oracle on Oct 14, 2008 16:07:42 GMT
May I ask a stupid question and query whether said chains were tried out to see if they worked?
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mrfs42
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Post by mrfs42 on Oct 14, 2008 16:37:08 GMT
I would say 'Yes'; because the LMS was very particular about drafting its internal operating publications. I suspect that there would have been a series of tests to find the best way of using the chains.
Couldn't comment on whether they were used in anger.
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Post by tubeprune on Oct 14, 2008 18:15:46 GMT
Well, mrfs, your interpretation of the bell system is interesting. You mean that the bell rang as long as the flag touched the wires? The "S" sign stayed on as a reminder that the driver had been given the bell. On the trains, it was always a single stroke bell. I wonder why it would be different on the platform.
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Post by mrfs42 on Oct 14, 2008 18:40:21 GMT
I'm not saying that I'm absolutely correct in considering that they were a trembling bell; however the phrase 'loud sounding bell' in LMS instructions was generally taken to mean a trembler. In this case I think the bell would ring as long as the flag makes contact.
I suppose the possiblility of it being a trembler is centred around how far from the Motorman that the bell is mounted. If the bell is a fair way from the driving position, and with the windows closed a trembler might be more noticeable that a single stroke. I will add though, that this is pure speculation as I've never seen a photograph of the bells location on the platform relative to the Motorman.
We may never know.
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