Catch Points

Discuss the prototype and how to model it.
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Serjt-Dave
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Catch Points

Postby Serjt-Dave » Sun Jul 21, 2019 1:36 pm

Hi All. As I slowly make my way round my layout making track I've now come to the section with all the point work etc to be made up. Within this section there are three Catch Points to be constructed. I've never made a catch point before so need some advice please. On the Templot template it shows the catch point like the toe end of a normal turnout, is that correct? Basically a point terminating just after the switch blades. Looking at images of them this looks to me to be the case. Templot shows the blades just operated by one tie-bar, images show both one and tow tie-bars.

All Best

Dave

Pannier Tank
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Re: Catch Points

Postby Pannier Tank » Sun Jul 21, 2019 2:06 pm

Have you seen this Templot Video?

http://templot.com/companion/catch_points.php
Last edited by Pannier Tank on Sun Jul 21, 2019 7:15 pm, edited 1 time in total.
Regards

David

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grovenor-2685
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Re: Catch Points

Postby grovenor-2685 » Sun Jul 21, 2019 3:14 pm

In general terms you are correct, its just a pair of switch blades. If you have no other info on the prototype then do just that.
However there are many prototype variations depending on the site circumstances, date when built, whether they are operationally in use as trap points or catch points etc.
A layout plan would allow more specific connections.
Rgds

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Serjt-Dave
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Re: Catch Points

Postby Serjt-Dave » Sun Jul 21, 2019 3:53 pm

Hi David, no as there was no link to refer it too. LOL. But I will look on the Templot site.

Hi Keith. I didn't think I could find any images of the catch points on my chosen layout {Edington Junction} but low and behold here's one. By the looks of it it's a single bladed type {which will make constructing them a lot easier} and the stock rail looks like it's bent/angled towards the ground. All three catch points at Edington protect the sidings {UP, Down and Bridgewater sidings}. The image shows the catch point on the Up siding with train leaving the bay platform heading towards Bridgewater.
Branch train leaving and signal loading gauge.jpg

John Palmer
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Re: Catch Points

Postby John Palmer » Sun Jul 21, 2019 6:42 pm

Dave, single tongue traps seem to have been quite common on the Branch; you will find another example in pictures of the Ashcott siding, and we have one at Burnham protecting the goods yard exit. I don't think I had seen that shot of 43218 when I did the plan, so all I could do was put in full switches in the positions indicated by the signalling diagram. My best guess now is that all three traps at Edington were single tongued, but pictures showing the trackwork seem to be rare, so you may have difficulty in confirming what was there.

I see that the S&DRT website now gives details of a range of pictures of Edington that it can supply. Many of these are by David Milton, to whom we were indebted for his coverage of Burnham, but unfortunately it appears that his photographic survey was done long after the Bridgwater Railway tracks were lifted (in 1956, I think?). But milepost 0 was still in situ!

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grovenor-2685
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Re: Catch Points

Postby grovenor-2685 » Sun Jul 21, 2019 6:58 pm

The MOT requirements for 1950 required double tongued trap points unless otherwise approved, also required a sufficient length of lead rail or other means to guide vehicles derailed at them away from the passenger line. However this was not retrospective and many existing single tongue traps remained in use until closure. The 1928 MOT requirement just required safety points without any further stipulation.
Anyway its good you have found some evidence.

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Re: Catch Points

Postby Pannier Tank » Sun Jul 21, 2019 7:16 pm

Serjt-Dave wrote:Hi David, no as there was no link to refer it too. LOL. But I will look on the Templot site.


Whoops, how embarrassing ! Post edited and link included.
Regards

David

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Serjt-Dave
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Re: Catch Points

Postby Serjt-Dave » Mon Jul 22, 2019 4:16 pm

Hi All.

David, thanks for adding the link.

Keith, by the looks of things Edington kept it's single bladed {tongued} catch points till the end which wasn't to long after the 1950 requirement. I'll keep looking for other images before I commit rail to timber but as John P says in all likelihood they were all the same.

John, your probably right saying all the traps would be all of the same type and plus if you say they were used in other locations on the line. Yes I'll be ordering some of those images especially the ones of the cattle dock. The image of 43218 you can just see the cattle dock under the loading gauge but I can't see the goods shed! You can see a sort of curved light coloured roof but it looks too low down and further back and behind the buffer stops?

Back to the catch point. I am right in thinking the derailing stock rail has been bent down towards the end?

Dave

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Re: Catch Points

Postby John Palmer » Mon Jul 22, 2019 6:58 pm

After looking at the picture as reproduced in the 'Norman Lockett Archive' I find it very hard to draw any conclusions about that stock rail. I'm inclined to think that the end of the rail is partially obscured by long grass, and that the rust/discoloration on the rail head where it diverges from the line of the siding may be creating a bit of an optical illusion in this respect. I have come across nothing to indicate that the stock rail was cranked downwards on either the Ashcott or Burnham traps, and I can think of no good reason why it would have been at Edington.

The curved, light coloured feature to which you refer must surely be too low to be the roof of the goods shed. If you haven't been able to find any pictures of this the best I can do is refer you to plate 44 of 'Burnham to Evercreech Junction' in the Middleton Press' Country Railway Routes series. You can make out what must be the corner of the goods shed protruding beyond the end of the station building and beneath the canopy. It's no more than a tantalising glimpse of a building with a curved roof, probably corrugated iron. The only building I can call to mind on the S&D that remotely resembles it is on the platform at Henstridge, and probably served as the road box store there. But that looks significantly shorter than the building glimpsed in the Edington shot.

Have you taken a look at what's available at https://www.somersetheritage.org.uk? Not much for Edington, but the site provides RAF vertical photographic coverage of an extensive area that includes Edington and dates from about 1946. Unfortunately one of the tiles for Edington is a bit blurred, but that containing the station platform and goods yard shows a light coloured structure in a position and of a size that is approximately correct for the goods shed, but on the other side of the siding from its position as shown in all the plans I've seen. So, is this the goods shed? If it is, it must have been moved at some time, but the photograph is evidence that the structure lasted until after the War.

That RAF photographic coverage is interesting for S&D enthusiasts, and sheds some additional light on the sizeable extent of the US petrol handling facility erected at Highbridge during the War. Much more extensive than is suggested by Judge & Potts or the R A Cooke track diagram.

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Serjt-Dave
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Re: Catch Points

Postby Serjt-Dave » Mon Jul 22, 2019 8:59 pm

Hi John. I remember seeing a catch point on the Up line at Windsor Tunnel in an Ivo Peters book and sure enough it was a single bladed one even on a mainline in 1956. Thankfully Mr Peters took a close up of the trap and the rail is straight at the end. So to be on the safe side I'll keep it straight.

I know the image your on about that just shows the top corner of the good shed. Thankfully I do have a copy of a design drawing of the shed so I can get dimensions etc.

Dave

John Palmer
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Re: Catch Points

Postby John Palmer » Mon Jul 22, 2019 11:04 pm

Another sprung catch tongue can be seen at https://www.flickr.com/photos/midsomer-norton-south-station/7264176960/in/album-72157629882634822/, in this case within a mile of the summit at Masbury.

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Noel
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Re: Catch Points

Postby Noel » Tue Jul 23, 2019 8:46 am

I've no idea what the official rules were, but a case can be made in principle that catch points on gradients and trap points against conflicting movements have very different purposes and therefore different requirements, so that what is done for one is not a guide to what is done for the other.

Catch points are there to prevent unfitted stock from running back and hitting something. Given absolute block working, there is no prospect of a following train being involved in a derailment that results from catch point operation. The risk to trains on the other line is also minimal as the derailment will be away from that line in all cases.

Trap points presuppose a potential conflict involving stock or a train on one line and a train on the other, where the block won't provide protection, because one is doing something in breach of the block rules. In such cases it is very much more important that any derailment is in the safest direction and does not obstruct the running line [on which a train may have already been accepted].
Regards
Noel

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grovenor-2685
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Re: Catch Points

Postby grovenor-2685 » Tue Jul 23, 2019 9:49 am

I think you would have to look very hard indeed to find an example of sprung run back catch points that were double tongue, single tongue were the norm for these. The MOT 1950 requirement for double tongue was specific to traps and did not apply to run back catch points.
Rgds

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Will L
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Re: Catch Points

Postby Will L » Tue Jul 23, 2019 3:46 pm

Noel wrote:I've no idea what the official rules were, but a case can be made in principle that catch points on gradients and trap points against conflicting movements have very different purposes and therefore different requirements, so that what is done for one is not a guide to what is done for the other.


Glad somebody else thinks that trap and catch points we actulay different things. Not my area of expertises but that is what I thought too.

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grovenor-2685
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Re: Catch Points

Postby grovenor-2685 » Tue Jul 23, 2019 4:16 pm

When considering operations and the requirements come from operations then this topic concerns 'Trap points', so defined in the 1950 requirements but also sometimes called 'Safety points' and so defined in the 1928 requirements. Trap points come in many varieties and are often just the non-mainline end of a crossover. In the days of unbraked freight wagons there was a requirement, on running line gradients, to protect against runaway wagons and operationally this was often done by 'Catch points', so called in the 1950 requirements. In the 1928 requirements these were called 'Self-acting throw-off switches'.
Now the trouble comes when, instead of the operating terminology you look at the permanent way department terminology for the physical object which sometimes called the object used as a trap point a 'Catch point' on the drawings.
NB Current P-way practice is to call trap points 'Trap points' eg Railtrack spec CE/S/049 section D.7.1, of course catch points in the operating sense are no more.
Rgds

Tony Wilkins
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Re: Catch Points

Postby Tony Wilkins » Tue Jul 23, 2019 4:20 pm

Serjt-Dave wrote:Hi All.
Back to the catch point. I am right in thinking the derailing stock rail has been bent down towards the end?
Dave

Hi Dave.
Highly unlikely. The diverging stock rail (which would be part of a standard switch unit) will be supported on timbers and chairs for its full length and thus will be level with the adjacent switch rail.
I have seen the very end of the stock rail cut at an angle, but this is not common practice.
Regards
Tony.

John Palmer
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Re: Catch Points

Postby John Palmer » Tue Jul 23, 2019 6:57 pm

grovenor-2685 wrote:Now the trouble comes when, instead of the operating terminology you look at the permanent way department terminology for the physical object which sometimes called the object used as a trap point a 'Catch point' on the drawings.

This has repeatedly been the subject of Templot discussions - e.g. http://85a.co.uk/forum/view_topic.php?id=2278&forum_id=11, which may also be of interest in the context of the Edington trap. It seems, from Martin Wynne's post #9, that up to 1971 the PWI's 'British Railway Track' always referred to a trap as 'catch points', but that this changed in the 4th edition published in 1971. A case of the terminology changing over the years.

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Serjt-Dave
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Re: Catch Points

Postby Serjt-Dave » Wed Jul 24, 2019 6:53 am

Hi All.

Hi Tony. I think your right. Looking at other catch point, traps or what else they are called none of them have a bent end rail. Looking at the example John P posted this clearly shows in fine detail the rail and chairs used etc. As John P said it may be where it has become overgrown with long grass etc which is giving the appearance of the rail cranked down.

The only thing I'm not quite sure about, would they have a leaver to operate or co-act with the cabin? Everything else {except the crossing gates] were operated via the Box. I can't see why the traps would have needed it's own leaver seeing where they are located I've attached the signaling diagram to show what I mean.
Signaling Layout 1948.jpg


All Best

Dave

andrewnummelin
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Re: Catch Points

Postby andrewnummelin » Wed Jul 24, 2019 8:09 am

Serjt-Dave wrote:Hi All.
...
The only thing I'm not quite sure about, would they have a leaver to operate or co-act with the cabin? Everything else {except the crossing gates] were operated via the Box. I can't see why the traps would have needed it's own leaver seeing where they are located I've attached the signaling diagram to show what I mean.
Signaling Layout 1948.jpg

All Best

Dave

lever 25: operates trap & point as you suggest.

levers 17 & 19: would be physically a challenge to operate 3 switches with one lever, but more importantly
19 reversed, trap 17 must be open to protect the running line
19 normal, trap 17 closed for shunting move but must be open to protect bay line, hence 17 & 19 can’t be worked by one lever.

Similarly, 11 has to be open to protect the down line whether 23 is normal or reversed but may be closed only if 23 is reversed.

Interesting that point lock 24 exists as this implies that passenger trains could leave the down platform in the up direction, but there’s no signalling for this.

Also note the absence of a lock on 25 so passenger trains could not arrive in the bay directly (via 25) from Bridgewater (but may depart this way).
19 reversed
Regards,

Andrew Nummelin

Terry Bendall
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Re: Catch Points

Postby Terry Bendall » Wed Jul 24, 2019 8:32 am

John Palmer wrote: that up to 1971 the PWI's 'British Railway Track' always referred to a trap as 'catch points', but that this changed in the 4th edition published in 1971. A case of the terminology changing over the years.


There is certainly some confusion in the railway modelling world about the terminology. Bob Essery's book "Railway Signalling and Track Plans" offers on page 29 the following definitions form the words of an old loco driver " Catch points catch you if you run back and trap points put you on the floor if you run too far forward.

My copy of the PWI's British Railway track is dated March 1971 so about the time that the definition may have changed. The requirement is "Where a siding joins a running line, the Ministry of Transport requires that a trap road be provided to ensure that any vehicle in the siding is diverted from the main line." Later the source states ""Trailing runaway catch points are frequently provided in running lines on fairly steep rising gradients to derail any vehicle which may happen to break away from a train and run backwards in the wrong direction." These definitions from an authoritive source support the elderly driver quoted by Essery.

I think that people may get confused over the use of one or two switch blades. The PWI's book states as follows:

"The following are the usual types of track roads:

(a) Single tongue trap - this consists of a single switch (blade), usually placed in the siding rail further from the main line. This have generally been superseded by the following

(b) Double trap points - These consist of a pair of switches and it is usual to make the switch rail nearer to the main longer than than the other.

(c) Trap point with crossing - In this type the rail nearer the main line is continued and a crossing inserted in the siding.

(dx) Trap road with stops - These form a dead end siding, which should be long enough to accommodate a vehicle clear of the fouling point between the trap road and the siding.

If we are trying to get things right then some sort of safety point, which is the generic description for such things, then they should be fitted in appropriate places. On Pulborough, which will be on display at Scaleforum this year we fitted a trap point at the end of the up loop and yard as per the prototype, and in line with the practice of the time, this was made using riveted sleepers and hand made blades. On Elcot Road, due to be show at the Uckfield show in October we fitted a trap point at the entrance to the yard and this was
made using the blades from an Exactoscale turnout kit. On Ravenscroft sidings a trap road with stops was fitted and this used a standard Exactoscale turnout.

As always, find out what happened on the prototype, then model it. :)

Terry Bendall

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grovenor-2685
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Re: Catch Points

Postby grovenor-2685 » Wed Jul 24, 2019 10:56 am

For the requirements then driver's reminiscences and PWI interpretation give a rough guide, but you can read the real documentation on line.
To save the googling I have attached two of them here
In the 1928 version traps are covered in section 9, pages 9 &10, catch points in section 16 page 11.
In the 1950 version traps in section 22, page 9 and catch points in section 37, pages 14 & 15.
MoT_Requirements1928.pdf
(1.61 MiB) Downloaded 13 times

MoT_Requirements1950.pdf
(15.73 MiB) Downloaded 7 times

And a couple of older ones if you want to research it further.
BoT_Inspectors1858.pdf
(248.14 KiB) Downloaded 4 times

BoT_Requirements1902.pdf
(2.83 MiB) Downloaded 6 times

John Palmer
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Re: Catch Points

Postby John Palmer » Wed Jul 24, 2019 11:03 am

A couple of notes on the signalling of Edington Junction:

1. Andrew's reference to 11 should instead be to 16 points - 11 was a push-pull lever controlling the ground signals in/out of Down Siding.

2. The c. 1930 diagram shows 20 as bolting both 19 east end and 25 points, yet the locking table describes 20 as nothing more than "FPL on 19 east end".

3. Although the c. 1948 diagram posted here shows 25 points unbolted, the locking table from that date shows it as being locked both ways by 20.

4. The inconsistencies between the diagram and the locking table for both 1930 and 1948 suggest that one or both are in error or incomplete. For operational flexibility I would have thought it desirable to maintain an FPL on 25 points, if only when lying normal. This would permit the simultaneous approach of trains both from Bridgwater and Highbridge, thereby facilitating connections for passengers between trains on the Bridgwater line and the main.

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Noel
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Re: Catch Points

Postby Noel » Wed Jul 24, 2019 11:26 am

Serjt-Dave wrote:The only thing I'm not quite sure about, would they have a leaver to operate or co-act with the cabin? Everything else {except the crossing gates] were operated via the Box


Catch points on gradients had to have hand levers, so that they could be held closed against the spring in situations such as wrong line working. There was no connection to any box. Trap points relating to running line access would only ever have been worked from the box or a ground frame released from the box, as they would have been an integral part of the locking system. The gates are locked from the box, so can only be opened [by a porter, possibly] with the signalman's permission.

andrewnummelin wrote:Interesting that point lock 24 exists as this implies that passenger trains could leave the down platform in the up direction, but there’s no signalling for this.


Possibly for access to the down siding? Or to permit a train to reverse onto either line to allow another down train into the platform, no signals being provided as it's rarely done and flagged from the box?

andrewnummelin wrote:Also note the absence of a lock on 25 so passenger trains could not arrive in the bay directly (via 25) from Bridgewater (but may depart this way)


John Palmer wrote:2. The c. 1930 diagram shows 20 as bolting both 19 east end and 25 points, yet the locking table describes 20 as nothing more than "FPL on 19 east end".3. Although the c. 1948 diagram posted here shows 25 points unbolted, the locking table from that date shows it as being locked both ways by 20.


There is a puzzle here. 8 will cater for shunting moves, so what is 7 for? Also, although the symbol is different, is 24 not a FPL?. If so, 7 could be there to permit access to the bay via 21, 23, and 26, the train having first been stopped at 4.
Regards
Noel

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grovenor-2685
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Re: Catch Points

Postby grovenor-2685 » Wed Jul 24, 2019 11:59 am

Noel wrote:
andrewnummelin wrote:Interesting that point lock 24 exists as this implies that passenger trains could leave the down platform in the up direction, but there’s no signalling for this.

Possibly for access to the down siding? Or to permit a train to reverse onto either line to allow another down train into the platform, no signals being provided as it's rarely done and flagged from the box?

Given that the bay is not signalled for arrivals (subject to the doubtful fpl on 25) 24 may be provided to allow arriving branch trains to back out and move to the bay for departure, in which case 11push would need a route to the Bridgewater line, what does the locking chart show?
although the symbol is different, is 24 not a FPL?. If so, 7 could be there to permit access to the bay via 21, 23, and 26, the train having first been stopped at 4.

24 is clearly an fpl as discussed above, by different symbol do you mean the bar symbol next to 26? In the above diagram this appears to be labelled 26 not 24, that would make it a fouling bar worked with 26 points although its not apparent why it would be needed.

Sight of the locking charts would help. The above diagram appears to have been drawn up by an enthusiast and may well have errors, does the same apply to the other availble signal plans and locking charts?

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steamraiser
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Re: Catch Points

Postby steamraiser » Wed Jul 24, 2019 12:06 pm

Ground signal 7 could allow shunting moves to pass signal 4 at danger up to GS 8.

Gordon A


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