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Unusual trap/catch point


JZ

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When you say CWR compatible what makes them so? Are they inclined switches or vertical with twist rails? I have encountered a new one that is causing a headache.

 

Inclined switches to save on the twist rails, stress transfer blocks between the switch and stock rails to transfer the thermal forces from one rail to the other.

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I presume it applied nationally but it was certainly standard practice on the Western for breather switches (expansion joints) in cwr to be mounted on timber sleepers and they used to come pre-assembled like that.

 

All adjustment switches used to come mounted on four timbers, except that in some places on the ER they only used the middle two and without strap rails. This was also done on the LM but only for temporary adjustment switches that would only be in for a week or so to protect plant rails during relaying. A special thickness of timber was used for adjustment switches (6 1/2" if I remember rightly) so that the bottom of the timber was at the same depth as the neighbouring full depth concrete sleepers. Some people would mount adjustment switches surrounded by the shallow depth EF / EG sleepers on ordinary crossing timbers, but that was going better than the standards, and would only occur to those who knew why the normal timbers were thicker in the first place. Now you can get special steel and concrete bearers to mount your adjustment switches on, which saves the extra maintenance caused by having timbers.

 

 

Below are a couple of photos of less usual types of Adj Sw that may be of interest.

 

1959%20FB%20Adj%20SW2.jpg

 

1959 dated Flat Bottom type.

 

 

1959%20FB%20Adj%20SW.jpg

 

Close up of one blade.

 

 

Modern%20type%20BH%20Adj%20Sw%202.jpg

 

95lb RBS Adj Sw.

 

 

 

Then getting back more to the original subject.

 

Inclined%20FB%20spring%20worked%20B%20tr

 

A sprung inclined B trap.

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  • 4 weeks later...
  • 2 weeks later...
  • 2 weeks later...

These could be stressed through? 

 

After searching through some paperwork i have on Sandy i came across this plan for a  switch and crossing renewal...

 

post-4034-0-29749800-1440792430_thumb.jpg

 

There appears to be some significant anchoring of stock and switch rails that i guess is to do with stressing in CWR?

 

This photo shows similar..

 

https://www.flickr.com/photos/blue-diesels/8340756567/

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Yes the five blocks you can see in the photo would each have two high tensile V bolts through them to transfer the stress from switch to stock rail. So the catch point can be used in CWR without the protection of adjustment switches.

 

The lead in the foreground of the flicker photo looks a bit dodgy, the zig zag of steel in the nearer switch suggests it is strengthened, but its pair mate appears not to be.

There are fishplated joints between it and the diamond so that bit of track is not CWR, however the other side might be as years ago it was considered acceptable to use S&C to separate CWR and jointed. Although the S&C would usually be strengthened, and either welded and/or fitted with tight jointed fishplates.

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The lead in the foreground of the flicker photo looks a bit dodgy, the zig zag of steel in the nearer switch suggests it is strengthened, but its pair mate appears not to be.

 

You would only need the reinforcement on one side if only the straight route is stressed. I have several plans for S&C renewal from the GN mainline including a mechanically operated D12 in the up fast at Arlesey that show the strengthening on one side only. I believe it was a 100/40mph turnout.

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Jointed track behind it so no through stressing on either side, and may not be CWR beyond the crossing either as we can not see that.

 

But it is an interesting thought about not needing strengthened switches both sides if only one of the roads beyond the crossing is CWR.

I have not heard of that being done, and the office I worked at liked its S&C as big strong welded up lumps. But that does not stop some other office at a different time or place seeing it your way.

 

I can only think of one lead I have come across that was only strengthened on one side, and memory suggests that one was strengthened on the wrong side for your theory. It is also possible that one or both could be the result of an ordering mistake by the maintainers. Or putting in anything that fits in an emergency with the intention of coming back later and fitting the proper spare.

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  • 2 months later...
  • RMweb Gold

may as well add this here, ground frame operated catch point at sinfin

 

the frame

6C1502F5-DB5C-4620-8572-9E269F2B2023.jpg

 

C5B55512-C71D-4CAA-9A2E-27E27CEE2CA5.jpg

 

and the points

1E79A931-6EC2-464C-96AD-657C5303BFF2.jpg

 

the train is sat up hill of the points in the old sinfin central station, you can see the back of the stopboard on the right that you can only pass once the points are set, the direction of the points is quite unusual as anything that may run away down the hill would run through the points and probably just throw them over

 

can anyone in the know enlighten me as to why they are set up that way, the line used to have a passenger service to sinfin (where the 56 is sat) and beyond the frame is a single line (old mainline to chellaston) with a turnback into the discharge facility

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can anyone in the know enlighten me as to why they are set up that way, the line used to have a passenger service to sinfin (where the 56 is sat) and beyond the frame is a single line (old mainline to chellaston) with a turnback into the discharge facility 

I would assume that the trap was added when the passenger service was started as the required trapping protection of the passenger line from goods lines and sidings. 

When Derby PSB was opened the Chellaston line was a through siding.

See http://www.norgrove.me.uk/signalling/plans/Derby.gif

Regards

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Interesting to see coal used as ballast!

 

I guess it's a question of using what you have available cheaply and in quantity.

 

A few years ago I did some design work for a salt company (mostly bulk chemical  feedstock rather than Saxa) and they were keen on using salt for "earthworks" like vehicle ramps, loading docks and so forth. They'd just pile it up to shape with a loader and bulldozer, hose it down for a while to melt the surface together and then leave it for a while. It set like concrete.

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  • 4 months later...
  • RMweb Gold

How about this one? A motor operated wide to gauge spring trap point...

https://www.flickr.com/photos/32297024@N08/26360088270/

 

with an enlargement of the point in question..

 

https://www.flickr.com/photos/32297024@N08/26027589564/

 

Now to find a photo of it!

 

This has some similarities but no spring involved as far as I could see (probably because it would only ever be used in the facing direction in normal working) - Sydney (NSW), with a separate machine for each switch rail

 

post-6859-0-38943200-1461581340_thumb.jpg

 

post-6859-0-92204400-1461581348_thumb.jpg

 

The ones at Perth (Scotland) were also purely for trapping and didn't appear to be trailable in any way - they used a single normal BR pattern hydraulic point machine with cranks to reverse the throw of the switch rails.

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How about this one? A motor operated wide to gauge spring trap point...

https://www.flickr.com/photos/32297024@N08/26360088270/

 

with an enlargement of the point in question..

 

https://www.flickr.com/photos/32297024@N08/26027589564/

 

Now to find a photo of it!

Clearly dual purpose, acting as both trap and catch point, presumably the branch was uphill.

The one in Sydney is just for trapping so no need of any spring action.

Similarly the one in New St. which could have been the same as the Sydney one but they fudged it by adding a separate single blade trap so that the turnout blades could retain their tie bars.

Regards

 

Edit, changed Perth to New St, should have looked at the picture caption.

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  • RMweb Gold

Clearly dual purpose, acting as both trap and catch point, presumably the branch was uphill.

 

 

No - the way it is arranged it is trailed by a train coming onto the branch where it goes from double to single so no need to pull any levers for it to go through the point - note the switch rail on that side is bolted in the open position for a  train coming off the branch but doesn't otherwise move.  So in reality it is a spring point which can be bolted in its normal (open) state as it has to be when the point is facing while the motored switch rail is effectively the trap as it is the only one which moves to let a train through towards the main line.  

 

Whether it was done like that to also act as a catch point is an interesting question but it certainly saved lever movements.

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  • RMweb Gold

This has some similarities but no spring involved as far as I could see (probably because it would only ever be used in the facing direction in normal working) - Sydney (NSW), with a separate machine for each switch rail

 

attachicon.gif061_DS~1.jpg

 

attachicon.gif060_DS~1.jpg

 

The ones at Perth (Scotland) were also purely for trapping and didn't appear to be trailable in any way - they used a single normal BR pattern hydraulic point machine with cranks to reverse the throw of the switch rails.

Pneumatically operated ,excellent

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  • RMweb Gold

There are a set of motor operated wide to gauge catch points on the down goods outside Colchester box. They were bullhead but renewed in flat bottom about six years ago

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No - the way it is arranged it is trailed by a train coming onto the branch where it goes from double to single so no need to pull any levers for it to go through the point

Which bit of my statement are you saying "No"  to?

Actually you have to pull lever 42 to go through the point as 42 unlocks it allowing it to push over against the spring.

If there was no need for it to act as a catch then lever 42 could have just closed the blade directly.

By being sprung it is available to catch any breakaways without needing 42 replaced.

Regards

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  • RMweb Gold

Which bit of my statement are you saying "No"  to?

Actually you have to pull lever 42 to go through the point as 42 unlocks it allowing it to push over against the spring.

If there was no need for it to act as a catch then lever 42 could have just closed the blade directly.

By being sprung it is available to catch any breakaways without needing 42 replaced.

Regards

 

Sorry yes - 42 has to be pulled to allow it to work as a spring (different practice form our neck of the railway where FPLs stand bolted with the lever reverse).  

 

But in any case 22 will catch/derail any breakaways whether 42 is bolted or not.

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