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Midland Railway tappet control tables and locking charts

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Midland Railway tappet control tables and locking charts

Unread postby Wiltssignal » Thu Jan 5, 2017 11:37 am

Does anyone have copies of control tables (mechanical and electrical) and a locking charts ("dog" chart) for a Midland Railway tappet frame? I am particularly looking for details of how point machines, colour light signals and back-locking/approach locking is controlled from a Midland tappet lever frame when intermixed with semaphore signals. Examples of the later REC or LMS 1943 frames will also be useful, although I accept that the later frames were not 6" pitch so the locking charts will be different. Any information gratefully received.

I've moved this post to "S&T" as I suspect you are more likely to get a response here. John
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Re: Midland Railway tappet control tables and locking charts

Unread postby Fast Line Floyd » Thu Jan 5, 2017 1:28 pm

Wiltssignal wrote:Does anyone have copies of control tables (mechanical and electrical) and a locking charts ("dog" chart) for a Midland Railway tappet frame? I am particularly looking for details of how point machines, colour light signals and back-locking/approach locking is controlled from a Midland tappet lever frame when intermixed with semaphore signals. Examples of the later REC or LMS 1943 frames will also be useful, although I accept that the later frames were not 6" pitch so the locking charts will be different. Any information gratefully received.

I've moved this post to "S&T" as I suspect you are more likely to get a response here. John

Such implementation would not have involved the mechanical locking but rather the electrical locking being implemented through electric lever locks and controllers.

My avatar is Cricklewood Junction which had an REC frame.
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Re: Midland Railway tappet control tables and locking charts

Unread postby John Hinson » Thu Jan 5, 2017 6:55 pm

Wiltssignal wrote:Examples of the later REC or LMS 1943 frames will also be useful, although I accept that the later frames were not 6" pitch so the locking charts will be different. Any information gratefully received.

I don't think I have have any data for you but don't rule out the 6" variation of the 1943-pattern frames which was specially designed for direct replacement of Midland Tumbler frames.

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Re: Midland Railway tappet control tables and locking charts

Unread postby Pete2320 » Thu Jan 5, 2017 11:38 pm

Fast Line Floyd wrote:Such implementation would not have involved the mechanical locking but rather the electrical locking being implemented through electric lever locks and controllers.
My avatar is Cricklewood Junction which had an REC frame.

In fact there will be very little difference between the way this is done on an MR frame and any other. However there will be significant differences between the types of equipment used, perhaps an extreme example would be Ketton which has the electric locks installed in typically Eastern Region fashion above the frame.
Last edited by Pete2320 on Tue Jan 10, 2017 3:19 pm, edited 1 time in total.
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Re: Midland Railway tappet control tables and locking charts

Unread postby Wiltssignal » Fri Jan 6, 2017 11:33 am

John - I had already posted a previous request in the "S&T Department" section (see "Control Tables - help Wanted") with no response, which is why I decided to try again in the "Heritage" section.

I have a background knowledge of mechanical locking and practical experience with Western Region frames (tappet and stud), Southern Region (Stevens and Westinghouse tappet) and LNWR tumbler frames, I am looking for any and all information I can get regarding Midland 6" tappet frame so that I can prepare a proposal for a new installation. I appreciate that the use of point machines (or more likely it will be clamp locks) and colour light signals relate to the electrical controls, but I would also like to know how the general mechanical locking is arranged on a Midland frame.

Hence my request for mechanical and electric control tables, locking charts and anything else which would be useful.

Examples;
Is it 4-bar or 5-bar locking? I believe the later 1943 LMS 6" frames were 5-bar locking whereas the Midland 6" frames were 4-bar locking.
How is the locking drawn on the locking chart? I know from experience that the way to draw a WR tappet locking is different to how a Stevens or Westinghouse tappet locking.
Do Midland frames use shelf plungers or catch handle contacts to activate the lever locks? I understand the frame to be used was originally fitted with "Northampton Locks" which are horizontally mounted under the operating floor. This method will be reproduced. I have worked on these locks when fitted to LNWR tumbler frames where a catch handle contact is used to pick the lock. Are catch handle contacts used on Midland frames?
Is it normal practice on a Midland frame to use a back lock (B)L on the signal lever in place of approach locking for power operated points?

The ideal would be to obtain a set of drawings for a site which has a mixture of semaphore and colour light signals, mechanical points with track locked FPLs and a point machine. Maybe a lot to ask for but any information what so ever is welcome.
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Re: Midland Railway tappet control tables and locking charts

Unread postby kbarber » Fri Jan 6, 2017 12:22 pm

A colleague on this site has a dog chart for the 1967 frame at Marylebone. Interestingly, it bears a note saying "1943 tappet 4 1/2" centres (it was undoubtedly a 4.5" frame). I'm reluctant to distribute it further without his say-so, but he was generous enough to let some of us have copies so I imagine he'll be willing to help.

Electric locks on these frames activated by catch-handle contacts - the tappet extended beyond the back of the locking tray and ran through a circuit controller mounted there, in contrast to the tumbler frames that needed a plunger (vacuum plungers common on the MR main line approaching St Pancras towards the end) or some other kind of activation (I've seen pictures of the ER-style box behind the frame activated by a lug welded to the catch rod, it's possible there were also some kind of lever-mounted contact box too but I've never seen one of those).
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Re: Midland Railway tappet control tables and locking charts

Unread postby S&TEngineer » Fri Jan 6, 2017 2:36 pm

Have you tried contacting these people who can probably help: http://www.midlandrailwaystudycentre.org.uk/index.html

Lots of documents came up when I entered the words 'lever frame' in the search engine here: http://www.midlandrailwaystudycentre.or ... alogue.php
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