Unrecognised track feature on Amlwch branch line

[Daveg66]

Hello

I am building a model loosely based on two stations of the Anglesey Central Railway, Amlwch and Llangwyllog and have noticed in photographs of Amlwch in particular, there is a long bar alongside the inside of one of the running rails in the platform road which is connected via point rodding to the lever frame. There is a similar set up at Llangwyllog as far as I can see from one photograph - well, the operating mechanism appears to be visible in the photo anyway.

 

As the station was closed in 1965 and then subsequently demolished, I do not have any photographs taken by myself and any shown on the internet are likely to be copywrited so I shall just include a small snip of an example of the facility.

 

It is purely for interest that I ask but I shall possibly try to incorporate a representation of it in my model, so the big question is, can anyone please tell me its purpose? It may be a retarder of some sort, not that the platform was on a steep  gradient as far as I am aware so any information would be gratefully received.

 

Many thanks

 

Dave

 

[phil-b259]

I believe thats whats known as a fouling bar. Think of it as an early type of track circuit as if a vehicle is stood over it then the wheels will prevent the bar from being lifted. Said fouling bar is connected to a lever in the signal box - and untill that lever is operated then point levers are locked and cannot be moved.

 

On the up side it needs no electricity to keep working and is ideal for remote or lightly used lines.

 

The downside is that there is a practical limit on how long a fouling bar can be and still be workable by a human pulling a mechanical lever, plus it cannot actually go through the point itself or split into two like track circuits can.

Edited October 2, 2021 by phil-b259

[ikcdab]

What I was about to say! 

Typically these devices are found at the toe end of a facing point, connected to the FPL. This prevents the FPL being unlocked if a train is stood over the points. In that situation I understand it's called a lockbar. There is one still in operation at Blue Anchor. Where they are not associated with FPLs then they are called fouling bars, I'm just struggling at the moment to think of an applicable situation.

[Daveg66]

Thanks very much for the very quick responses - at Amlwch it was definitely leading up to the toes of the points at the end of the loop so this would mean the points couldn't be changed if the train was within the lockbar length of the toes.

 

The one at Llangwyllog appears to be at the heel end of the points at the southern end of the Down loop assuming it is the same piece of equipment. Perhaps it prevented the points from being changed if a train was over it because then it may have been within the fouling point.

 

I got interested in these features because I have just started to use Modelu 4mm LNWR point rodding stools and couldn't work out why a single point at the south end of the loop required three rods. One for the tiebar, one for the FPL but I was baffled by the third but a photo in the Middleton Press Main Lines Bangor to Holyhead including the Anglesey branches was the only picture I have been able to find which shows this end of the loop at Llangwyllog, the only station on the line where trains were permitted to cross.

 

With regard to the rodding stools - amazing things and they (in conjunctoin with square section rodding) really add something to the look of the p-way.

 

Thanks again for the quick responses - I knew this would be the place to ask the question - I shall see if I can find any photos of Blue Anchor now!

[ikcdab]

5 minutes ago, Daveg66 said:

work out why a single point at the south end of the loop required three rods. One for the tiebar, one for the FPL but I was baffled by the third but a photo in

Hmm....Im not sure that three rods would have been required. There are still only two signalbox levers, one for the blades and one for the FPL. The lockbar is driven at the point. I can't remember now, but I seem to recall that at Blue Anchor, the FPL rod is connected to the lockbar and movement of the lever moves the lockbar. Movement of the lockbar then drives the FPL. I have some photos somewhere that I will dig out.

[Daveg66]

Intersesting article describing Indian Railways practice, which I would think might be rather similar to UK practice in a number of ways:

https://civilcrews.com/interlocking-of-signals-and-points/

 

[Daveg66]

 

Thanks IKCDAB. This is another snip, at the south end of Llangwyllog station near the loop points. There was only one point here and the device between the rails shown in the book I referred to. I assumed that the 3 point rods were related to the points and the mechanism.

 

Excuse the poor quality but it is a photo of a photo but you can just make out the mechanism in the bottom left of the picture. It does seem to be in an odd place given the use of lockbars.

 

[melmerby]

IIRC the fouling bar is moved from one position (locked) to the other (unlocked) before the points can be changed, then it is moved back to the locked position.

Obviously it can't move if there is a vehicle over it.

 

I watched one being operated, some time back.

Edited October 2, 2021 by melmerby

[Michael Hodgson]

Here's a slightly wavy one at Weybourne on the North Norfolk Railway

 

[Compound2632]

Once upon a time these were standard features - before track circuits. They were a constraint on bogie passenger carriage development as the distance between the inner axles of the bogies could not be greater than the length of the locking bar - typically 40 ft, IIRC - otherwise it would be possible to change the facing point under the carriage.

[Bucoops]

Liverpool St had them and the cost and disruption to alter them to suit longer coaches is one of the reasons given for the former GE line to get 52'6" mainline coaches instead of the LNER standard 61'6".

[Compound2632]

3 hours ago, Bucoops said:

Liverpool St had them and the cost and disruption to alter them to suit longer coaches is one of the reasons given for the former GE line to get 52'6" mainline coaches instead of the LNER standard 61'6".

 

I expect that the Great Northern had had a long-term programme of extending locking bars whereas the less wealthy Great Eastern hadn't. But that is the best explanation I have seen for the use of shorter carriages on the GE section.

[The Stationmaster]

22 minutes ago, Compound2632 said:

 

I expect that the Great Northern had had a long-term programme of extending locking bars whereas the less wealthy Great Eastern hadn't. But that is the best explanation I have seen for the use of shorter carriages on the GE section.

A facing point lock(ing) bar had to be as long as the the greatest distance between the wheels on the vehicles which passed over it.  Hence the GWR with 70ft vehicles (and no doubt any other company with very long vehicles0 had to use long lock bars and these were very often divided into two parts which, obviously, linked in the drive to the facing point lock.

 

Facing point lock(ing) bars and fouling bars perform(ed) two entirely different functions and although mechanically similar (although electric fouling bars were quite widely used) were used in different ways.  The lock(ing) bar is a rising bar while a fouling bar is a depression bar.  

 

The purpose of the lock(ing) bar was to ensure that facing points in passenger lines were securely bolted in position, via the facing point lock, as a train passed over the points thereby ensuring that the points could not be moved under a train - which would obviously lead to a serious derailment (e.g Wigan 1873).  Therefore lock(ing) bars would/will always be found immediately in rear of, or through, the switch rails of a facing point on a passenger line.  When the point is locked the bar is in its lower position and cannot rise as wheels pass over it thus holding the bolt securely in the facing point lock.  This is what can be seen in the photo posted by the OP.

 

A fouling bar would be found at the heel, or trailing end, of a point, and was intended to make sure that a movement had passed clear of the fouling point where the two lines di.verged from the point.  In this case the bar normally stood raised leaving the points free to move but when a train or vehicle was standing foul of the points the bar would be depressed by the wheels and that would lock the point in whichever position it was set towards.  Fouling bars were normally used where Signalmen had a poor view of the points and could not clearly see if a train or movment  had passed clear of those points or sometimes at very busy locations where points were being moved frequently in order to keep heavy traffc moving.

 

Depression bars (of the electric variety) could also be found in some  larger stations near the stop blocks where locos might stand for some time and track circuits could not be relied on to operate effectively.

[Stubby47]

Nothing to do with the track mechanicals, but I took this photo last week of the footbridge near Llyn Cefni.

 

 

[PenrithBeacon]

Broad Street station on the NLR had them too

[Compound2632]

2 hours ago, PenrithBeacon said:

Broad Street station on the NLR had them too

 

Any facing point anywhere on a passenger-carrying line had them until such time as they were rendered redundant at that location by the installation of track circuits (if that ever happened - see @PenrithBeacon's reply below). The locking bar is, in essence, a mechanical track circuit - it detects the presence of a train.

Edited October 2, 2021 by Compound2632

[PenrithBeacon]

Thank you for that Steven. The devices at Broad Street were rendered redundant by the withdrawal of services followed by the demolition of the station.

[w124bob]

The 2mm Association publish a booklet on point rodding which includes some details, it's only £7 and well worth it regardless of your chosen scale. Here is the link 7th one down http://www.2mm.org.uk/products/nms/index.html

[Daveg66]

Thanks all for the wealth of information. 

I suspect that the bar at Llangwyllog was a fouling bar then because it appears to be at the heel end of the loop points.

 

Llangwyllog points and signals in the immediate station area where controlled from the external lever frame. Even though this was raised on a brick base, if a down train was in the platform, the porter-signalman would probably not be able to see the up end of the loop very easily and the fouling bar would certainly prevent the points being set in reverse to allow an up train to depart if the down train was within the fouling point.

 

So, it appears that we have a lock bar at Amlwch and a fouling bar at Llangwyllog.

 

Because of the way my model is set up, all I need is the three point rods as the points would be where my cassettes are. As I mentioned originally I think, the layout is only based on these two stations but I'm trying to capture the essence of them and make elements of them recognisable.

 

Thanks again.