Pencarrow: nothing to see, move along please.

[2ManySpams]

OK, ignore the order of the numbering, that needs  sorting later, but here's my latest interpretation of levers, locks and fouling bars:

 

 

Any comments, corrections, amendments welcomed - I'm on the very edge of my comfort zone here!

[St Enodoc]

OK, ignore the order of the numbering, that needs  sorting later, but here's my latest interpretation of levers, locks and fouling bars:

 

ScreenHunter_475 Mar. 12 20.42.jpg

 

Any comments, corrections, amendments welcomed - I'm on the very edge of my comfort zone here!

That looks about right to me based on:

 

https://signalbox.org/diagrams.php?id=642

 

You could do worse than following the number sequence there too.

[2ManySpams]

That looks about right to me based on:

 

https://signalbox.org/diagrams.php?id=642

 

You could do worse than following the number sequence there too.

That's the exact same diagram I've had half an eye on. I'm sure though that Pencarrow is sufficiently different to introduce areas where I can't follow Bodmin North's example.

[2ManySpams]

One area that won't work practically on the layout due to the amount of compression is the fouling bar 5 at the end of the platform.

 

I'm not sure how long the bars are yet but presume longer than the gap between the two inner wheels on a coach? The problem I have is that a departing train in the platform road is likely to be sat on the fouling bar at departure. If the fouling bar actually worked this, if my understanding is correct, would mean crossover 4 could not be pulled. Fine for a passenger train heading for Boscarne / Wadebridge but not OK for a freight heading for Wenford.

 

What are the alternatives? What does an electric track circuit look like / require?

 

Help appreciated.

[2ManySpams]

Another query relates to how to actually model a fouling bar? On the real railway they align with, and are depressed by, the wheel flange.

 

The one marked as 7 will definitely be on the scenic section and will visually be noticeable. I'm going to discount any thoughts of a working bar. Due to scaled down mass I can see such a feature causing derailments or lumpy running. So, some sort of long strip in the depressed position is needed?

[2ManySpams]

Does anyone have any of the 7mm Exactoscale bridge chairs kicking around they don't want? I could do with another 18 to correct the mistake above on another 5 turnouts and finish off the final turnout.

rps20180312_142222.jpg

Happy to pay and for postage.

A big thank you to Daifly for coming to the rescue on this one.

[3 link]

Another query relates to how to actually model a fouling bar? On the real railway they align with, and are depressed by, the wheel flange.

The one marked as 7 will definitely be on the scenic section and will visually be noticeable. I'm going to discount any thoughts of a working bar. Due to scaled down mass I can see such a feature causing derailments or lumpy running. So, some sort of long strip in the depressed position is needed?

Hi Chris,

 

On the subject of fouling bars, below is a grainy diagram of one, although it seems they were classed as a part of a facing point lock and also called a locking bar. In google search there are a couple of photos in images, so not a lot to go on.

 

 

Regarding the bridge chairs I'm fairly certain the only GWR 4 bolt chairs were the slab and bracket chair which was fitted under the vee's and some of the elbow chairs. The bridge chair ( L1 chair ) was just a 2 bolt chair.

 

Martyn.

Edited March 13, 2018 by 3 link

[Siberian Snooper]

Another query relates to how to actually model a fouling bar? On the real railway they align with, and are depressed by, the wheel flange.

 

The one marked as 7 will definitely be on the scenic section and will visually be noticeable. I'm going to discount any thoughts of a working bar. Due to scaled down mass I can see such a feature causing derailments or lumpy running. So, some sort of long strip in the depressed position is needed?

 

The detection bar is 50ft something long and if there is insufficient space on the inside of the rail, IE another turnout in close proximity, then a different sort were fitted outside the rail. I think there was a thread on here about the various types. 

 

Track circuits require insulated fishplates either end of the track circuit and bonding wires on all the other fishplates. Here's a link to some bonding wire pictures,

 

https://www.google.co.uk/search?q=fishplate+bonding+wires&client=firefox-b&dcr=0&tbm=isch&tbo=u&source=univ&sa=X&ved=0ahUKEwiz9Kei6ujZAhWKA8AKHcelBiYQsAQIQQ&biw=1366&bih=654

 

The  most usual sort are in the picture on the 2nd row down and 4th picture along.

 

Found the thread

 

http://www.rmweb.co.uk/community/index.php?/topic/122722-train-detection-bars-or-treddles/

[Metropolitan H]

One area that won't work practically on the layout due to the amount of compression is the fouling bar 5 at the end of the platform.

 

I'm not sure how long the bars are yet but presume longer than the gap between the two inner wheels on a coach? The problem I have is that a departing train in the platform road is likely to be sat on the fouling bar at departure. If the fouling bar actually worked this, if my understanding is correct, would mean crossover 4 could not be pulled. Fine for a passenger train heading for Boscarne / Wadebridge but not OK for a freight heading for Wenford.

 

What are the alternatives? What does an electric track circuit look like / require?

 

Help appreciated.

Which signal controls the departure of a train on the Wenford branch? - Presumably the ground shunt signal associated with platform starter F, on the grounds that there are no passenger moves on this branch?

 

Assuming the above is correct, then you can't have a fouling / locking bar operative before signal F - AND no train loco can pass signal(s) F until one or other of them is pulled off.

 

Is this right? / Does it help?

 

Regards

Chris H

[St Enodoc]

That's the exact same diagram I've had half an eye on. I'm sure though that Pencarrow is sufficiently different to introduce areas where I can't follow Bodmin North's example.

Understood Chris, but you should be able to follow the principles for lever numbering. 

[Simond]

Confused dot com...

 

One of my wagons was retro-fitted with sprung W irons. Runs beautify. I was convinced that the springing units were produced by either Parkside or more likely Slater's. Can I find them on either of their websites? Nope.

 

 

might also look here

 

http://www.westernthunder.co.uk/index.php?threads/bill-bedford-w-irons.6773/#post-164435

 

best

Simon

[2ManySpams]

Many thanks to Dave (Daifly) for this very kind donation to the cause, very generous:

 

 

Corrective actions can now continue!

 

Cheers Dave.

[daifly]

Hi Chris

 

Glad to be able to help!

 

Dave

[brossard]

Slaters spring units:  https://slatersplastikard.com/others/7mmParts/wagonParts/gOwagonFittings.php #71546  I think I prefer these.

 

For Parkside, I've used Bill Bedford springing units as well:  https://eileensemporium.com/index.php?option=com_hikashop&ctrl=category&task=listing&cid=1289&name=7mm-components&Itemid=189 In a couple of instances the steel spring wire has been so corroded as to be unusable.  I've been able to get spring wire from a music supply shop - guitar string.

 

John

Edited March 14, 2018 by brossard

[The Stationmaster]

One area that won't work practically on the layout due to the amount of compression is the fouling bar 5 at the end of the platform.

 

I'm not sure how long the bars are yet but presume longer than the gap between the two inner wheels on a coach? The problem I have is that a departing train in the platform road is likely to be sat on the fouling bar at departure. If the fouling bar actually worked this, if my understanding is correct, would mean crossover 4 could not be pulled. Fine for a passenger train heading for Boscarne / Wadebridge but not OK for a freight heading for Wenford.

 

What are the alternatives? What does an electric track circuit look like / require?

 

Help appreciated.

 

 

One area that won't work practically on the layout due to the amount of compression is the fouling bar 5 at the end of the platform.

 

I'm not sure how long the bars are yet but presume longer than the gap between the two inner wheels on a coach? The problem I have is that a departing train in the platform road is likely to be sat on the fouling bar at departure. If the fouling bar actually worked this, if my understanding is correct, would mean crossover 4 could not be pulled. Fine for a passenger train heading for Boscarne / Wadebridge but not OK for a freight heading for Wenford.

 

What are the alternatives? What does an electric track circuit look like / require?

 

Help appreciated.

Right first to the naming of the parts and what we are talking about here are facing point lock bars (sometimes called Facing Point Locking bars).  Fouling bars serve a very different purpose and can sometimes work in a different way from a lock bar depending on the mechanism used.

 

Right that's the simplest bit but the next bit isn't much worse and it will help first to understand the purpose of the lock bar - which is to prevent facing points moving under a passing trains.  The way in which this is done is shown in the sketch in Post No. 6782 above the rodding run from the signalbox operates the locking bar (which moves vertically although in reality the end of it rises through an arc due to the arrangement of the mechanism) and the facing point lock or bolt is driven off the locking bar.  The bolt in turns runs within a casting surrounding the front stretcher bar of the point and that stretcher bar has notches cut in it which the bolt engages - this part of the process appears in the pic below -

 

 

 

This shows a bit of the mechanism albeit driven by a point machine but you can see how the bar works.

 

http://www.warwickshirerailways.com/gwr/gwrbsh1672.htm

 

The way in which the whole assembly works is as follows - the lever in the signalbox works the locking bar via the rodding run and the locking bar in turn drives the bolt to lock the stretcher bar.  When the point is locked (usually with the signalbox lever standing reverse but there were variations from this) the bolt is engaged in the stretcher bar and the locking bar is in its lower position.  The passage of train wheels prevents the locking bar from rising thus the point is held locked under a passing train.  When it is required to move the point the lock lever is replaced to normal which cause the locking bar to rise and the bolt to disengage, then the point can be changed.  One important thing to note is that sometimes the point would only lock and bolt in one position but with a connected lock bar it will inevitably be locked in either position so there will be two notches in the stretcher bar however with an inside bar (see below at Birmingham Snow Hill it is possible that only one route through the point would be locked

 

Because it is a 'belt & braces' device to lock the points the position and length of the locking bar can be critical.  Usually the ideal siting would be to place the locking bar in rear of the the point toe but in advance of the protecting signal.  there are pictures of this on the 'net but usually in a view of something totally different and alas I haven't any pictures of my own of the arrangement.  In this case the locking bar has to be as long as the longest wheel base of any vehicle likely to pass over the point - the GWR with 70ft vehicles had some very long locking bars in some places

 

This picture shows the answer to Spams' problem at the platform end.  Again it is electrically driven but that minor difference is irrelevant because what is clearly given is that here the bar is inside the switch rail - the usual way of doing the job when a signal is tightly in rear of the point toe.  Note too that because both routes are locked there is a bar inside each switch rail.  There would conceivably be no need to lock the route leading from the platform to the siding so only the passenger route would be locked and the FPL lever would not release the ground signal reading to the siding. 

 

http://www.warwickshirerailways.com/gwr/gwrbsh1367.htm

 

Hope that helps a bit!!

 

 

 

 

Edited March 14, 2018 by The Stationmaster

[The Stationmaster]

Oh and the track circuit (unlikely at Bodmin North but you never know) would largely be invisible apart from possibly some lineside battery cupboards.  However if you are modelling the point mechanism in detail it will make a big difference because the locking bar won't be there - a whole lot simpler in that respect and the rodding run will instead directly drive the FPL bolt mechanism.

[The Stationmaster]

OK, ignore the order of the numbering, that needs  sorting later, but here's my latest interpretation of levers, locks and fouling bars:

 

ScreenHunter_475 Mar. 12 20.42.jpg

 

Any comments, corrections, amendments welcomed - I'm on the very edge of my comfort zone here!

 

And now to the diagram.  Bodmin North appears not to have involved push or pull levers for ground shunting signals so they'll all be individually numbered so that's one possible question out of the way.  The big question mark comes with the main line spring slotted catch point and its position in relation to Signal C.  I don't know if you've found any photos or better plans but the distance between Signal C and the catch point looks to be excessive and would need either a very long lock bar (all the way from the signal to the points!) or there was a track circuit there.  George Pryer's diagram shows the catch point on the station side of the overbridge but John Hinson's diagram post dates the 1937 removal of the catch point in the opposite direction so it is possible it was moved by 1950.  I would be inclined to say that there was a track circuit at Pencarrow and forget about the distance!

 

The ground signal labelled E was, according to George's diagram a yellow arm signal - which definitely fits the layout when the siding served the gas works.  Whether you go for a a yellow arm signal (lovely little things in their standard Southern Railway form) depends on how you see that siding being worked.  The rest of the diagram is ok, apart from numbering, although you might care to think about also providing a semaphore signal reading to the platform alongside signal D but it might overpowrer the scene so is as much as scenic and 'visual impression' matter as signalling in this case.

[2ManySpams]

Thanks Mike, will have a good look at your posts when I get home.

[2ManySpams]

Mike,

 

Here's the very obscure catch situated on the Real Bodmin North by the bridge.

 

http://forum.signalbox.org/viewtopic.php?f=2&t=3542

 

http://www.bluebell-railway-museum.co.uk/archive/photos/jjs/b99/085.htm

 

No, I won't be modelling it!

[St Enodoc]

Right first to the naming of the parts and what we are talking about here are facing point lock bars (sometimes called Facing Point Locking bars).  Fouling bars serve a very different purpose and can sometimes work in a different way from a lock bar depending on the mechanism used.

 

Right that's the simplest bit but the next bit isn't much worse and it will help first to understand the purpose of the lock bar - which is to prevent facing points moving under a passing trains.  The way in which this is done is shown in the sketch in Post No. 6782 above the rodding run from the signalbox operates the locking bar (which moves vertically although in reality the end of it rises through an arc due to the arrangement of the mechanism) and the facing point lock or bolt is driven off the locking bar.  The bolt in turns runs within a casting surrounding the front stretcher bar of the point and that stretcher bar has notches cut in it which the bolt engages - this part of the process appears in the pic below -

 

IMGP6898.jpg

 

IMGP6900.jpg

 

This shows a bit of the mechanism albeit driven by a point machine but you can see how the bar works.

 

http://www.warwickshirerailways.com/gwr/gwrbsh1672.htm

 

The way in which the whole assembly works is as follows - the lever in the signalbox works the locking bar via the rodding run and the locking bar in turn drives the bolt to lock the stretcher bar.  When the point is locked (usually with the signalbox lever standing reverse but there were variations from this) the bolt is engaged in the stretcher bar and the locking bar is in its lower position.  The passage of train wheels prevents the locking bar from rising thus the point is held locked under a passing train.  When it is required to move the point the lock lever is replaced to normal which cause the locking bar to rise and the bolt to disengage, then the point can be changed.  One important thing to note is that sometimes the point would only lock and bolt in one position but with a connected lock bar it will inevitably be locked in either position so there will be two notches in the stretcher bar however with an inside bar (see below at Birmingham Snow Hill it is possible that only one route through the point would be locked

 

Because it is a 'belt & braces' device to lock the points the position and length of the locking bar can be critical.  Usually the ideal siting would be to place the locking bar in rear of the the point toe but in advance of the protecting signal.  there are pictures of this on the 'net but usually in a view of something totally different and alas I haven't any pictures of my own of the arrangement.  In this case the locking bar has to be as long as the longest wheel base of any vehicle likely to pass over the point - the GWR with 70ft vehicles had some very long locking bars in some places

 

This picture shows the answer to Spams' problem at the platform end.  Again it is electrically driven but that minor difference is irrelevant because what is clearly given is that here the bar is inside the switch rail - the usual way of doing the job when a signal is tightly in rear of the point toe.  Note too that because both routes are locked there is a bar inside each switch rail.  There would conceivably be no need to lock the route leading from the platform to the siding so only the passenger route would be locked and the FPL lever would not release the ground signal reading to the siding. 

 

http://www.warwickshirerailways.com/gwr/gwrbsh1367.htm

 

Hope that helps a bit!!

Nice views of the FPL cover too Mike - thanks.

[2ManySpams]

The 3 page thread on the signal box forum is interesting to read:

 

http://forum.signalbox.org/viewtopic.php?f=2&t=3542

 

It would appear that Bodmin North had quite a few interesting features that confound the experts.

 

Did make me laugh that somebody was quite insistent that the box was of brick construction. Photos clearly show otherwise...

 

I think this is the same mob that tore strips off Treneglos. Don't feel so bad no that they can't tell the difference between brick and stone ;-p

[The Stationmaster]

The 3 page thread on the signal box forum is interesting to read:

 

http://forum.signalbox.org/viewtopic.php?f=2&t=3542

 

It would appear that Bodmin North had quite a few interesting features that confound the experts.

 

Did make me laugh that somebody was quite insistent that the box was of brick construction. Photos clearly show otherwise...

 

I think this is the same mob that tore strips off Treneglos. Don't feel so bad no that they can't tell the difference between brick and stone ;-p

 

There are one or two people on that site who might best be described as 'anally retentive' (in a less than helpful manner).

Edited March 15, 2018 by The Stationmaster

[2ManySpams]

There are one or two people on that site who might best be described as 'anally retentive' (in a less than helpful manner).

I've read quite a few threads on that site where the experts insist that what is clearly evident in reality couldn't possibly exist because the rule book says so. In my experience rule books are a good place to start but can't cover every eventuality and in many fields you need to come up with local variations. Problem is that a lot of the reasons for these variations are lost in time...

[2ManySpams]

Mike Stationmaster, you have a PM...

[2ManySpams]

Whilst I'm mulling over how best to model the FPLs etc I'm afraid I've gone back to doing a spot of wiring. Sorry chaps, I know it's dull but it needs doing.

 

Board 3 marked up: