GWR Type B single tongue catch point

[PUASHP]

Dear all I need some assistance please.

 

I am looking to build a couple of single blade catch/ trap points for my GWR layout Hembourne as part of the Cameo Layout challenge. These points will protect the run round loop and the goods siding onto the branch line.

 

I am building in 4mm scale EM gauge using C&L components but I have not idea how best to fix the single blade and then make it operate using a Tortoise point motor.

 

I have a photo of the point (ignore the scotch block) and the drawing from the GWR switch and crossing practice book.

 

Any help would be most appreciated.

 

Paul

[Gordon A]

Replace one of the plain track chairs with a piece of 0.6mm copper clad glued to the sleepers and soldered to the switch blade.

I use super glue gel.

Use the same drive as you would on a normal point.

It is after all half of a pair of blades in a normal point.

 

Gordon A

[Stephen Freeman]

Not sure using the same drive would work with just 1 blade, the stretcher bar would probably be waggling about a bit. Try soldering a piece of tube to the blade and locate the Tortoise drive shaft in that. You'll probably also need to keep the blade from lifting, so a short bit of rod under the stock rail soldered to the blade should do the trick.

[Trog]

You'll probably also need to keep the blade from lifting, so a short bit of rod under the stock rail soldered to the blade should do the trick.

 

 

It is called a kicking strap, in 12" to the foot scale track, and is normally an extension of the stretcher bar.

[Tim V]

That doesn't look like a type B in the picture, more like a loose heel switch - probably a 9'.

[Vanders]

Hang on, I'm really confused now: what stretcher bar? If there's only one blade, what would it be "stretching"? What is that in the drawing, then?

[Gordon A]

That is a stretcher bar that enables the single blade to be connected to the single point rod running down the elft hand side of the track in the picture.

 

Gordon A

[Grovenor]

A single blade does not have a stretcher bar, the connection is just a drive rod.As Vanders said, a stretcher bar links the two switches of a pair to keep them at the correct spacing.

Regards

[Stephen Freeman]

Rather confusingly the reference to a Type B catch point has nothing to do with the catch point in the photo, reference to the GW Study Group Book will show other types of single blade catch points as well as double ones too.

[Tim V]

As I said, that looks like a loose heel switch, this one at Hampton Loade in 1976 is similar. I believe this has been replaced with a two bladed catch (so much for preservation...). as can be seen, the round stretcher passes through the stock rails, to stop the blade from lifting. Note the age of the chairs.

[Stephen Freeman]

How many modellers drill through the blade for the stretcher bar? Not many I guess especially in 4mm scale. As for the SVR example, I'm afraid H&SE and or the Railway Inspectorate rules probably made them change it.

[Tim V]

Or, it wore out. Look carefully, those chairs are inside keyed. I saw they resleepered the back siding at Highley that was laid with inside keys, but looks like Hampton Loade's siding was not similarly treated.

 

Edit - found a later picture of the back siding at Highley it had been resleepered by 1992 but ordinary keys by 2008.

Edited May 9, 2017 by Tim V

[Gordon A]

Tim's excellent pictures show the earlier type round bars that pass through the web of the rail used in early point work as opposed to the later metal strips that pass under the rails..

I do not when the strip bars were introduced.

 

Gordon A

[NorthHighlander]

How many modellers drill through the blade for the stretcher bar? Not many I guess especially in 4mm scale. As for the SVR example, I'm afraid H&SE and or the Railway Inspectorate rules probably made them change it.

I do! And it can be a right pain if you've already installed the switch as I had!

[NorthHighlander]

Maybe it's me, but I think there is a disconnect between the very first post in this thread and the later images of the round stretcher bar passing through the web of the blade and stock rails, which has not, in my opinion, been clarified. The drawing from the GWSG book shows, not a flexible bar stretcher passing under the rails, but the round rod passing through them. The actual drive rod to the lever is attached to the tip of the switch blade and, I believe, attached to a detection bar on the ground signal?

Edited June 18, 2017 by NorthHighlander

[Grovenor]

Maybe it's me, but I think there is a disconnect between the very first post in this thread and the later images of the round stretcher bar passing through the web of the blade and stock rails, which has not, in my opinion, been clarified.

The photos may well not show the same type of connections as the drawing. But there is also a disconnect within the two photos, the top one shows a drive rod coming in from the far side, but then the lower picture has no sign of the drive rod at all. Maybe the drive is lugged onto the round bar and the joint is all hidden behind the signal in the top photo

The drawing from the GWSG book shows, not a flexible bar stretcher passing under the rails, but the round rod passing through them. The actual drive rod to the lever is attached to the tip of the switch blade and, I believe, attached to a detection bar on the ground signal?

The switch extension piece just carries the detector connection.

Its difficult to tell in the photos whether the round bar is connected to the blade and hence can be part of the drive, or just passes through a hole in the blade to hold it down.

Regards

Edited June 19, 2017 by Grovenor

[Tim V]

Looking at the GWSG book, the picture that accompanies the drawing in fig 34 looks like the later replacement catch point at Hampton Loade! How about that for coincidence! It wasn't till today I looked at my copy.

 

Turning to the catch point in the first picture at Bacton, as I've said this does not look like a B type switch, but most likely, as suggested in the GWSG book a 10' loose heeled switch.