Historic Point Motors

Discuss the prototype and how to model it.
BrockleyAndrew
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Historic Point Motors

Postby BrockleyAndrew » Mon Oct 15, 2018 11:02 pm

I've just been reading Two Centuries of Railway Signalling, which I bought some time ago for its photographs of Borough Market Junction, and the section before a chapter on Southern Railway electrification of track and signalling (1920s/30s) mentions how early electric frane systems mimicked mechanical lever systems. So the Westinghouse electric frames (K&L) still have mechanical frame style levers (but smaller and still hand pulled) and a panel of electrically lit indicator bulbs above the levers (the first time I saw photographs of these panels I immediately thought of the "futuristic" control panels in the 1970s Tardis!).

Southern Way issue #13 has photographs of relaying of track at Borough Market Junction and has a caption referring to a possible temporary ground frame in the foreground of a photograph, near the point motor and opposite the Signal Box, controlling the point motors during the relaying of track in the 1940s.

My question as a novice is about the mechanical vs electrical operation of the point motors. I have looked online at the wbsframe.mste.co.uk and it is very informative but for the non professional I still can't work out some basics, sorry.

Do the Westinghouse (1920s) frames (electric) still have mechanical connection to the point machines? Do they mechanically activate the motors which do the remote electrically powered job of switch movement. Or is the connection through wiring? Sorry if this is a completely naive question.

Does an electrical frame still interlock mechanically within itself but interface electrically with its points?

The more I try to research the more I realise how little I know. But what is confusing me is the temporary frame photographed in 1940s during relaying. Is this a levered structure because levers are the recognised vocabulary or is there a mechanical command to the point motor.

Andrew

In Brockley, London

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grovenor-2685
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Re: Historic Point Motors

Postby grovenor-2685 » Tue Oct 16, 2018 9:19 am

My question as a novice is about the mechanical vs electrical operation of the point motors. I have looked online at the wbsframe.mste.co.uk and it is very informative but for the non professional I still can't work out some basics, sorry.

Do the Westinghouse (1920s) frames (electric) still have mechanical connection to the point machines? Do they mechanically activate the motors which do the remote electrically powered job of switch movement. Or is the connection through wiring? Sorry if this is a completely naive question.

The connection to point machines is by electric wiring, a power franme does not have provision for connection to rodding.

Does an electrical frame still interlock mechanically within itself but interface electrically with its points?

Both options were used, power frames could have mechanical or electrical locking.

Getting into details becomes a big topic. :)
regards

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jon price
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Re: Historic Point Motors

Postby jon price » Tue Oct 16, 2018 9:22 am

Not sure about the South, but when the LNWR began to use electrical boxes and signals the system (patented by Webb and Thompson in 1897) had semaphore and rotating ground signals and turnouts run on servos, and electric light in the signals, but the interlocking frame was mechanical. The signals could have been electric light rather than mechanical semaphore, but it was decided that uniformity across the system would be safer. This was the same reason put foward for using miniature levers rather than following American and European practice of rotary switches. Gresty Lane became operational by 13th January 1899, and the nine Crewe cabins by July 1907.

BrockleyAndrew
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Re: Historic Point Motors

Postby BrockleyAndrew » Tue Oct 16, 2018 11:58 am

Thanks Keith and Jon,

I had assumed that a power frame would communicate with the point motors by electrical cabling. Can I post a phone shot of a detail of a photograph published in Southern Way to illustrate a question about the temporary frame in the photograph?

Many thanks

Andrew

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grovenor-2685
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Re: Historic Point Motors

Postby grovenor-2685 » Tue Oct 16, 2018 12:12 pm

Yes, with an acknowledgement.
Rgds

BrockleyAndrew
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Re: Historic Point Motors

Postby BrockleyAndrew » Tue Oct 16, 2018 1:10 pm

Thanks Keith,

My question was about the temporary frame. The article by Grahan Hatton has a photograph on p.90 of The Southern Way Issue No 13 and the note to the photograph (p.91) mentions the relaying of track progressing in stages, and suggests this "required disconnecting of the mechanical rodding between the various stages" and this is why a temporary ground frame is used and notes that this would explain the lever numbers being unsequential - that they match their normal signal bix lever numbers.
He also does write "The points appear to be motor-operated, but mechanically connected to the frame in some form, so how the system worked is unknown".

Why would there be mechanical rodding for a point motor?

Andrew

BrockleyAndrew
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Re: Historic Point Motors

Postby BrockleyAndrew » Tue Oct 16, 2018 1:14 pm

Here is the detail from the photograph
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IMG_20181016_111344.jpg

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grovenor-2685
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Re: Historic Point Motors

Postby grovenor-2685 » Tue Oct 16, 2018 1:23 pm

Difficult to be sure what is going on from that picture, as the relay boxes are hiding the rodding cranks. But the most likely situation is that the point motors are temporarily disconnected with the rodding passing underneath to the point stretcher.
Regards

BrockleyAndrew
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Re: Historic Point Motors

Postby BrockleyAndrew » Tue Oct 16, 2018 1:46 pm

Thanks so much Keith,

That makes perfect sense. I just hadn't realised that might be a possibility!

So the relay boxes are permanent, not the rodding which is in place during the track replacement!

Btw does each point motor have its own relay box? Please do point me to a text/book if this is all fairly basic.

Thanks again

Andrew

Enigma
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Re: Historic Point Motors

Postby Enigma » Tue Oct 16, 2018 1:49 pm

I saw the title and thought it might have been about these -

BLPointMotor1.jpg
BLPointMotor1.jpg (44.23 KiB) Viewed 815 times


BLPointMotorAd.2.A.jpg
BLPointMotorAd.2.A.jpg (166.34 KiB) Viewed 815 times


Somewhere I've got a few and they still seem to work OK.

BrockleyAndrew
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Re: Historic Point Motors

Postby BrockleyAndrew » Tue Oct 16, 2018 3:28 pm

Hello Enigma

Yes,sorry the title wasn't very precise.

Mark Adlington's website on Westinghouse Brake & Saxby signal frames has some details on a 1960s M3A point motor.

I assume the point motors in this shot are 1930s ancestors.

Andrew
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IMG_20181016_150338.jpg

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grovenor-2685
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Re: Historic Point Motors

Postby grovenor-2685 » Tue Oct 16, 2018 9:53 pm

The M3 series point motors were quite an old design by the 1960s. The new BR spec for point motors came out in the early 60s after which the usual Westinghouse supply was the 'Style 63'.

Those cast iron relay boxes did not hold very much, that looks to be a row of 6 boxes, doors to the right, with another slightly smaller one on the end of the row, door facing the camera.
Generally a point machine would not need relays just some terminal blocks to joint the cabling. Some of the boxes probably had track circuit relays and feed units.

Those BL point motors were costly, 18s/4d was a lot of money in 1960, probably intended for the GP Keen set. IIRC the H&M was significantly more economical.
Regards

BrockleyAndrew
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Re: Historic Point Motors

Postby BrockleyAndrew » Wed Oct 17, 2018 1:54 pm

Thanks for your help Keith.

A websearch for Westinghouse point machine came up with a (1920s) cigarette card on ebay!

Andrew
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Screenshot_20181017-143623.png

Brian Eves
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Re: Historic Point Motors

Postby Brian Eves » Wed Nov 07, 2018 11:43 am

Hi guy's
On the subject of electric lever frames, in the 1980's I had the "pleasure" of working on the Westinghouse frame at Liverpool Lime Street which has just been taken out of service.
The points in Lime Street were, by my time, clamplock hydraulic type.
I cannot remember if it had mechanical locking or just the electric locking by circuit controller and relays.
One little anecdote was when a colleague used meths to clean the front lever bands of dust and dirt. When the signaller used the levers for the first time after cleaning, there was a blue flash across the full front of the glass fronted cabinet. Thank god all my lever bands were at the back of the frame.

BPRS lever frames started out life as a pneumatic frames but were redesigned as electric operation. The GCR installed quite a few in the Immiming area when opening the docks in 1912.
In 1991, I attended my first solo wrong side failure investigation when a train full of chemicals had become derailed when a set of points had moved erroneously beneath the train. Fortunately no hard came to the contents of the train, otherwise North East Lincs would be missing from later maps. I spent the next year working out how the frame worked and how it was wired to the electric point and semaphore signal motors. The original drawing had been well lost and faulting was passed on by word of mouth.
The BPRS frame was unusual in that instead of a lever, it had a slide which was pulled out horizontally. This operation made and broke contacts upon the top of the slide. It also had Dymanic Indication fitted.
When a set of points were required to be reversed, the slide was pulled to the R Check position, a voltage was then sent down the reverse operating wire to the point machine. When the points had motored Reverse a set of contacts in the machine changed state and sent the back EMF along the Normal operating wire and energised a coil under the lever slide and propelled the slide fully Reverse. Therewere originally "Dolls Eye" indicators which indicated Normal or Reverse. Pushing the slide to N Check position normalised the points, utilising the Reverse operating wire to energise the same coil underneath the slide.
Signals were operated to Off in a similar manner but allowed to return to On under gravity, the signal motor would then act as a generator to operate its own coil beneath the signal slide.
Mechanical locking was fitted to the lever frame but I never got to redraw this part of the frame.
The result of my wrong side failure investigation was that two wired, one in the machine and one in the detector box of the SGE machine had become trapped under the lid. As both detection and motor were fed off the same 110V battery a short circuit occured. Over the years, safety features of the original design were "overcome". Had these been working correctly, the derailment would not have occured.
If anyone is interested in this type of frame, please drop me a line.


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