Jigs and Formers.

Jigs and Formers.

By Robert Law

13th October 2023

One of the other small jobs that has been done but probably has been missed by the untrained eye. Is the replacement of the signal lenses, or spectacles. Each semaphore signal is fitted with two. Red, Green. Or Yellow, Green for a distant signal. Luckily we have this from jig from Tyer & Co Ltd. This wonderful device is the cutting edge of 1950s design! Designed to reduce maintenance costs and speed up the repairs to signals with broken or missing lenses. 

This is a jig designed by the LMR. With its concept going back to the early 1950s. It has been a great help with the replacement of the polycarbonate lenses that we use on the railway. Glass lenses were commonly used up to the 1960s/70s. And before the modern days of rubber, window putty or metal tabs were used to secure the lenses in place.

Interesting we have received an early copy of the instructions of use that we thought we would share with you all

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Armed with all this information it was time to fit some replacement lenses around the railway.

So the first thing to be done is to put the rubber seal around the lens. Place the brass oval handle down into the jig. Remove a boot lace from your boot and rap it round the inside of the outside rim. With this done it then gets placed into the jig, with the boot lace on the inside of the brass former.

Once placed in the jig, close the back over to secure the lens in place. Then start to pull the boot lace round lifting the rubber edge up and placing it around the brass oval. Remembering to push the brass former down as you go round otherwise it can slip off and you need to start again.

Once the outside rubber seal has been lifted on the brass former it can be removed from the jig. Don’t have it out of the jig for too long as the rubber seal is under a lot of stress and it wants to get back to its original shape. As you can see on the left hand side of the picture.

The brass former is then passed through the spectacles plate with the outer edge of the rubber seal pushed firmly agents the spectacle plate. With this the brass former is then pulled out.

With the brass former pulled clear the rubber seal then moves back to its original form trapping the lens in the correct position.

Looking from the other side.

Various signal lenses have now been changed around the railway. Not a big job, but one we thought you would like us to share with you.

Boat North home signal with before and after

Boat South home signal before and after.

Lots more lenses have been changed around the railway. Have a look around and see if you can spot the difference.