Interlaced sleepering at points

Any aspect related to the structures and equipment on the Caledonian Railway Company.
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Jim Summers
Posts: 914
Joined: Tue Aug 14, 2012 8:54 pm

Interlaced sleepering at points

Post by Jim Summers »

A bit of debate has been taking place amongst those of a Highland Railway persuasion on interlacing and some interesting opinions have been emerging. I felt obliged to offer them Matheson's comments, which you will all have read in TTL of course, with an advert for the CRA, so I don't feel too bad about repeating on here an interesting contribution by Alastair Campbell of the HRS.

Any further comments welcome of course.

Below is the most recent exchange on the HRS discussion group.

"Wearing my Caledonian hat, I put an article in a recent "True Line" quoting the views of the Caley's Chief Engineer of the time (Matheson, in 1903) on everything, following a very intense visit to North America to study practice there. He dealt with interlaced sleepering and I attach what I wrote.

There was lots more in the article, but you'll have to join the Caledonian Railway Association to read it!

"Interlaced sleepering
Modellers agonise over the sleeper arrangements for point and crossing work, calling them ‘interlaced’ where the same size of sleeper is used throughout the turnout, making them look complicated. ‘Interlacing’ is not represented by the manufacturers of model track, but as the Scottish railways tended to hold on to that method, then interlaced it has to be on the model.

Not that Matheson actually uses the work ‘interlaced’, which may have been coined by modellers. He declaims: “In regard to the important matter of ‘sleepering’ of switches and crossings, it is noticeable that on American Railroads the general practice is to have long timbers of varying lengths for sleepers, these taking both the main and branch line rails throughout the entire length between the switches and crossings, whereas the practice on the Caledonian Railway is to have two distinct sets of sleepers laid alternately for the main and branch lines respectively. Keeping in view alignment, superelevation and the other requirements of a good junction, and the conditions peculiar to the British system of permanent way, the Caledonian practice of alternating the sleepers is probably the better, although on the other hand proximity of alternating sleepers renders packing difficult, and this has to be guarded against".

From: Alisdair Campbell
Sent: Thursday, September 13, 2012 9:57 AM
To: [email protected]
Subject: [hrschat] Re: INTERLASE POINTS

I remember coming upon an interlaced turnout in the badlands between Glasgow and Renfrew in the early 80's when carrying out a (road) bridge survey. It was still in use and was in reasonably good condition. I meant to go back with a camera and never did...

I believe that during the Second World War, interlaced turnouts came back into use for minor routes and sidings due to the low availability of longer timbers from the Baltic. I have a letter from Buchanan House from 1982 in response to a rather naive approach from me asking whether they had any drawings of HR interlaced turnouts impecunious student. In it, I was told that all they had was a drawing showing an LNER interlaced sleeper turnout dated 1946. Unfortunately, I never took up the offer to buy a copy...

The use of interlaced sleepers has advantages in the lighter weight and easier availability of standard sleepers. However, they can make packing below the sleepers difficult in some areas of the turnout, due to the lack of space between them, and tend to force out the distance between chairs reducing support to the rails. As axle loads got higher, this drove the industry to the use of the longer timbers.

I suspect that Keith's hypothesis of a constraint in the size of creosoting plant may also have had an influence.

They still seem to have been in common use in the early years of the 20th century. My understanding, based on no more than years of paying attention when the words interlaced sleepers came up in an article, is that the Scottish companies continued to use interlaced sleepers in general to a later date than those south of the Border.

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