Facing and Trailing Points

[The Stationmaster]

Well, I'm only trying to get to the bottom of things myself, as I'm sure you realise.

 

My information comes from Nock's Historic Railway Disasters, where he claims on p.48 that In those days the idea of any individual taking out a patent for any idea was anathema to higher management, and French instead of getting any credit for ingenuity got instead a sharp 'rap over the knuckles.' The situation was made so unpleasant that an outsider who was prepared to help French financially withdrew his support rather than be further involved.

 

Of course, Knock may be making this all up out of whole cloth, in which case obviously your setting of the record straight is exactly what's needed, so sincere thanks.

 

 

John - there are some authors whose work I tend to take with a pinch of salt as their research was not necessarily to the standards we expect nowadays. The problem we often face in research is that we sometimes come across 'information' (of the verbal kind) which has been 'handed down' and often got mangled or 'expanded' in the process.

 

And - particularly with some of the railway authors whose writings were popular in the 1950s & 60 - there is no doubt that things have sometimes had a dramatic, or simplifying, element injected and this can occasionally alter the meaning. I have long enjoyed, and had respect for, LTC Rolt's 'Red For Danger' - it taught me a lot in my youth. But when you read the reports of some of the accidents Rolt covers you quickly realise that they were not necessarily exactly as he has portrayed them. And - even more so when doing original research - you discover that the subsequent impact on safety which he attributed to some of them simply did not happen in the way he implies, if at all. As ever it is a case of caveat emptor with some authors - as much as it is when buying Rolex watches off a market stall.

 

The situation regarding patents was usually made quite clear by most Companies (and I expect the GNR took a similar line, but don't know) in that they usually considered themselves to have either free access to, or even ownership of, something patented by a member of their staff.

 

And sorry Mods to go off thread

[John_Hughes]

Actually, Mike, I do agree with you, which is why I'm quite happy to accept that Nock (and I!) may have got it wrong; and the situation about patents then after all was probably very similar to what many companies expect to apply today.

 

The books are, as you say, popular and not scholarly, and certainly 'boil down' the lengthy accident reports into very few words, so some errors of compression or misunderstanding are inevitable.

 

As Beast has truly said, it's good to get the facts straight and distinguish them from the myths. It's just that if Nock is indeed wrong, a little detail would be nice.

 

And, Mods, thanks from me too for your forbearance!

[jamie92208]

Totally off topic but as regards patents some employees were entitled to keep their royalties. On a tour of Wabtec at Doncaster I was told that Sir Nigel Gresley was paid £50 for each set of conjugated valve gear fitted to locos built abroad. (90 sets on the Union Pacific 3 cylinder 4-12-2's plus some other in I belive Australia and India). This would have been a considerable sum in the early 1930's. I presume that the LNER didn't pay Sir Nigel for the gear fitted to it's own locos.

 

On the subject of research O S Nock certainly used a lot of his material many times over in his later books but may well ahve done some original research when he started. I would suspect, but don't know that a lot of what he wrote came by word of mouth from railwaymen that he worked with particularly in the signalling field as he worked for one of the manufacturers.

 

I would concur with all the remarks above about research. I've done original research about the Midland's West Riding Lines, at Kew and in Bradford archives and my conclusions are at odds with a lot of the published sources as to how committed the Midland was to it's project.

 

Jamie

[Donw]

Jamie92208 mentioned the GWR using switched diamonds . I believe that Board of Trade brought in a requirement that obtuse crossing could not be used at greater than 1:8 not sure when it came in. Thus for high speed junctions switch diamonds would be needed.

Also the GWR in some cases such as Penrhyn near Falmouth prefered to put in a diamond and a trailing point rather than a facing point on a platform road. That must have been more expensive than an FPL.

Donw

[beast66606]

 

Also the GWR in some cases such as Penrhyn near Falmouth prefered to put in a diamond and a trailing point rather than a facing point on a platform road. That must have been more expensive than an FPL.

Donw

 

- a diamond and a trailing point do not replace a facing point - have you got some plans to post to show us what you mean ?

[martin_wynne]

- a diamond and a trailing point do not replace a facing point - have you got some plans to post to show us what you mean ?

Hi Dave,

 

Here is a photograph showing what Don means (Rubery on the Halesowen Railway): http://www.photobydj...romDownHome.jpg

 

(From this excellent site: http://www.photobydjnorton.com )

 

Here's another well-known picture showing a facing turnout being avoided: http://85a.co.uk/for...ment.php?id=350

 

To return to the original question, this is the connection to the engine shed and turntable at Kirkcudbright. A similar arrangement:

 

map of Kirkcudbright shed connection from the National Library of Scotland

 

regards,

 

Martin.

[jamie92208]

Thinking about the original question it probably didn't matter which direction the exit from a loco shed was as almost all the traffic would be light engines which could reverse quickly (Unlike today where the crews have to change ends) All locos going off shed would be turned so that they were facing in the correct direction for the service they were due to work. I would thus surmise that most connections would be trailing ones as this would save the expense of facing point locks.

 

Quite a few sheds had a turntable on the route to the exit From my own knowledge this applied to Lancaster. I think Stewarts Lane had this arrangement as well. As I mentioned before the companies only spent money where they needed to.

 

Jamie

[Peter Kazmierczak]

Also the GWR in some cases such as Penrhyn near Falmouth prefered to put in a diamond and a trailing point rather than a facing point on a platform road. That must have been more expensive than an FPL.

Donw

 

Yes, I think I know what you mean.

This was a very typical arrangement, particularly on the GW.

[The Stationmaster]

Yes, I think I know what you mean.

This was a very typical arrangement, particularly on the GW.

 

 

It was probably once upon a time the 'usual' arrangement in most places - after all the restriction on the use of facing points applied to all railways.

 

But what does seem to have happened is that it survived in a very noticeable fashion on GWR single lines, and had - of course - to be replicated when layouts were renewed because nobody was going to the expense of moving a goods shed or yard or providing extra FPLs and expensive signalbox re-locking (especially if shunting became more difficult).

 

Incidentally the connection at Penryn was not over a diamond crossing in the Down line but over a single slip - something which is probably even more 'GWRish' in this sort of situation. This arrangement was replicated in the 1923 (major) realignment of Penryn station so clearly served some sort of useful purpose although quite what is difficult to divine over 80 years after the event.

 

What often seems to be overlooked is that trailing points facilitate the shunting of yards and sidings because the loco is at the 'open' end and can readily propel the shunts. If you had facing access to a yard the loco would be between its train and the sidings it is meant to be serving - not a good idea!

 

Jamie makes an excellent point (sorry ) about the greater simplicity of reversing steam locos compared with most diesels, hence entering a depot over trailing points was hardly an inconvenience in steam days.

 

[martin_wynne]

Incidentally the connection at Penryn was not over a diamond crossing in the Down line but over a single slip - something which is probably even more 'GWRish' in this sort of situation.

Hi Mike,

 

Here's a picture showing exactly that: http://85a.co.uk/for...hp?post_id=3245

 

(Since identified as Three Cocks Junction).

 

regards,

 

Martin.

[beast66606]

Hi Dave,

 

Here is a photograph showing what Don means (Rubery on the Halesowen Railway): http://www.photobydj...romDownHome.jpg

 

Thanks Martin.

 

 

Looking at the photo it is possible to set back into the yard from the left hand running line a facing point would not give anything additional (and to depart away from us would mean propelling back onto the single line) to this as the loco would still be at the same end of the train, however a trailing connection allows access from the right hand running line without using facing points unnecessarily - as I have said, companies avoided them unless necessary and this is a situation where a facing point is not necessary.

[coachmann]

Single line lines seemed to differ as regards "facing" points, but I think the short answer is protecting trains. Facing points were obviously a weak link in this protection as was incorrect proceedure when speed restrctions were in force. Only guessing here, but the old bullhead points were probably weaker and more flexible than todays flat-bottom facing points.

[beast66606]

Single line lines seemed to differ as regards "facing" points, but I think the short answer is protecting trains. Facing points were obviously a weak link in this protection as was incorrect proceedure when speed restrctions were in force. Only guessing here, but the old bullhead points were probably weaker and more flexible than todays flat-bottom facing points.

 

Not sure I understand your point Coach but facing points were (and still are) frequently used to provide flank protection for trains, they are much more useful for this purpose than trailing points, when provided and sometimes they were provided purely for this reason (traps).

[coachmann]

By 'protecting trains', I meant trains would have to set back into a yard rather than diving headlong into them via facing points. I am going off th'owden days.

[The Stationmaster]

Hi Mike,

 

Here's a picture showing exactly that: http://85a.co.uk/for...hp?post_id=3245

 

(Since identified as Three Cocks Junction).

 

regards,

Martin.

 

And therein lies a very amusing little aside to some of the earlier debate in this thread. Prior to layout alterations in 1890 that single slip in the Down line was seemingly a facing point (with no connection from the Up). This might have reflected the way in which the Mid Wales Railway wished to protect its junction - the only company whose trains approached that facing point were those of the Midland Railway

 

(BTW the GWR made no alterations to the running lines until 1940 when loops were lengthened; it retained the MWR facing connections to two sidings - one of which was also on a part of the layout used by Midland Railway trains.)

 

Remarkably the site survives - albeit as a building materials etc supplier's yard although some of the trees are still there.

[The Stationmaster]

Single line lines seemed to differ as regards "facing" points, but I think the short answer is protecting trains. Facing points were obviously a weak link in this protection as was incorrect proceedure when speed restrctions were in force. Only guessing here, but the old bullhead points were probably weaker and more flexible than todays flat-bottom facing points.

 

I think you're right there Coach - altho' the decrepitude of the material plays an important part - in my experience bullhead pointwork was likely to be more seriously damaged under a derailment that flat bottom. The only exception to that was with a run through the old type of strecher bars were more likely to bend and thus reduce damage to switch rails.

 

However back in the snows of 1978 one of my Shunters ran an HST through the trailing end of a flat-bottom crossover which was part way over but snow/ice bound without doing any discernible damage at all whereas I have seen bullhead switch rails crippled in similar situations.

[Barry Rhys]

Single line lines seemed to differ as regards "facing" points, but I think the short answer is protecting trains. Facing points were obviously a weak link in this protection as was incorrect proceedure when speed restrctions were in force.

 

Hi Coach, I've been following this thread but I'm afraid I'm a little confused now. Assuming the single line is bidirectional (or is this where my misunderstanding arises?) I'm not sure what is being referred to as a "facing point", since wouldn't all points be "facing points" in one direction of travel?

 

I'm sure it's not an error, especially since both Beast and Stationmaster have understood and responded, so I'd be grateful if one of you would explain what is meant by a facing point at a single line location. Thanks.

 

Neil

[martin_wynne]

Assuming the single line is bidirectional (or is this where my misunderstanding arises?) I'm not sure what is being referred to as a "facing point", since wouldn't all points be "facing points" in one direction of travel?

Hi Neil,

 

At most stations on a single line railway the track becomes double through the station area. This creates a loop so that trains running in opposite directions can pass. The loop tracks are normally signalled uni-directional so that down trains use one side and up trains use the other side (left-hand running in the UK). Any points connections into sidings or engine sheds within the double track section will then be either facing or trailing to the direction of running on the relevant track.

 

regards,

 

Martin.

[StaffsOatcake]

In all incidents all points on a single line will be classified as facing points. As would any of those that are bi-directional line. Essential a facing point is any that the toe (switch end) is one that faces the on coming traffic (switches reached before the frog) and needs to be locked in some way. A trailing point is one that the traffic passes of the frog first and then the switch blades these do not need to have an FPL unless there is traffic that runs in the opposite direction that carries passengers, in which case it would become a facing point, it is the traffic flows that dictate whether it is facing or trailing.

 

With the advent of point motors, clamp locks the locking mechanism became part of the motor/drive system and detection is only given once the motor/drive unit is satisfied that the switch has moved and detection is proved.

 

 

The stock rails have to of a minimum standards and the 'weaker' argument of bullhead over flat bottomed does not fit as many locations had trains thundering over them in facing directions even in the days of steam engines way before flat bottomed rail became the order of the day. The newer flat bottomed rail is much heavier than the flat bottomed stuff that was laid in the 60's. The maximum axle loading in this country is still 25.5 tons and has been for many years

 

The pway, line speed, location and the angle of the switches (length of the switch blades) is what dictates the speed in which a point can be taken and more importantly what trains can run over them. Points that are classified A & B sizes (small) passenger trains are not allowed over them in the facing direction.

 

 

The switch sizes ranges from A to G with G been the longest and fastest(Colton Junction, near York is a 125mph facing point and uses G switches but the track is inter-laid for a much longer distance before the frog is reached)

 

To complicate things even more the Hydragas points used on the RETB system (cambrian/west Highland lines) don't have any kind of FPL as they rely on the pressure of the hydraulics in the rams and expansion vessel to keep the switch closed against the stock rail but have an approach speed of no more than 15mph

[beast66606]

In all incidents all points on a single line will be classified as facing points. As would any of those that are bi-directional line. Essential a facing point is any that the toe (switch end) is one that faces the on coming traffic (switches reached before the frog) and needs to be locked in some way.

 

(my bold)

 

Facing points on single lines are classifed as being facing for normal traffic, so the connections in the pictures which trail into the lines from the goods yards are not facing points.

 

A trailing point is one that the traffic passes of the frog first and then the switch blades these do not need to have an FPL unless there is traffic that runs in the opposite direction that carries passengers, in which case it would become a facing point, it is the traffic flows that dictate whether it is facing or trailing.

 

FPLs can be used on goods lines too - its mandatory for passenger lines but frequently provided for goods lines, if there is a trailing point which has a main route in the opposite direction its called bi-directional

[The Stationmaster]

 

With the advent of point motors, clamp locks the locking mechanism became part of the motor/drive system and detection is only given once the motor/drive unit is satisfied that the switch has moved and detection is proved.

 

Yes, but quite a number of point machines do not incorporate facing point locks as it was quite common for machines without FPLs and complate facing point detection to be installed on trailing points up to (and possibly later in some places) the early 1970s. Simple reason - machines without FPLs were cheaper. Nowadays I understand that they all come with FPLs - it being cheaper to have one standard arrangement off-the-shelf.

 

The stock rails have to of a minimum standards and the 'weaker' argument of bullhead over flat bottomed does not fit as many locations had trains thundering over them in facing directions even in the days of steam engines way before flat bottomed rail became the order of the day. The newer flat bottomed rail is much heavier than the flat bottomed stuff that was laid in the 60's. The maximum axle loading in this country is still 25.5 tons and has been for many years

 

The maximum axleload is actually 25 tons (British 'Long Tons') which is taken as 25.5 tonnes (Metric Tonnes). And yes, while bullhead points had 'trains thundering over them' they certainly weren't having to carry the axleloads (in particular) and speeds that have been in vogue since the 1970s - when there were campaign changes to instal flat bottom rail etc on those routes where high speed running was coming (especially where it would be mixed with heavy axleloads - with them also running quite fast). The damage which bullhead track sustains from heavy axleloads always seems to be quite considerable although age might also be a factor; I remember one PW Inspector saying he was cutting out inches of rail ends every year on one bullhead section purely because of axleload damage.

 

 

[StaffsOatcake]

Yes, but quite a number of point machines do not incorporate facing point locks as it was quite common for machines without FPLs and complate facing point detection to be installed on trailing points up to (and possibly later in some places) the early 1970s. Simple reason - machines without FPLs were cheaper. Nowadays I understand that they all come with FPLs - it being cheaper to have one standard arrangement off-the-shelf.

 

 

Don't think there any left on the network anymore but the old SGE (30v) machines had separate detection boxes and external FPL arrangements. So as you point out it wasn't always fitted. in my experience the actual motor unit was always fitted with the ability to operate an FPL whether it was used or not (this allowed interchangability). I have a great deal of experience of the machines I like to get the lids off and have a gander at the workings in them at the Festiniog railway whenever I go and do my bit for them. I'm not sure which other manufacturers continued with external detection and locking. I know that Westinghouse M series machines are integrated locking, as are HW and my favourite, to look at any way, the Metropoliatn Vickers Machines.

 

The maximum axleload is actually 25 tons (British 'Long Tons') which is taken as 25.5 tonnes (Metric Tonnes). And yes, while bullhead points had 'trains thundering over them' they certainly weren't having to carry the axleloads (in particular) and speeds that have been in vogue since the 1970s - when there were campaign changes to instal flat bottom rail etc on those routes where high speed running was coming (especially where it would be mixed with heavy axleloads - with them also running quite fast). The damage which bullhead track sustains from heavy axleloads always seems to be quite considerable although age might also be a factor; I remember one PW Inspector saying he was cutting out inches of rail ends every year on one bullhead section purely because of axleload damage.

 

 

 

All standard rail was 90lb per foot whether bullhead or flat bottom, current standard is 120lb per foot. As the rail at the top initially is the same profile whether bullhead or flat bottom the stretching of the rail is due to wear rather than the profile. It is the hammer blow that causes stretch and damage at the rail ends, frogs etc. Age is more likely to be a factor, modern rails have a slightly different composition are pre-stretched slightly to reduce expansion and reduce the buckling and the need to remove sections as they get ran over.

 

Sorry for the confusion over the metric tonne issue. Its 25 uk tons and 25.5 tonnes (actually 25.4). Mind a piece of published research has described the maximum axle loading as 250kn or 24.5tonnes. No wonder new track layouts get in a mess they're not laying the base for the line correctly in the first place.

[StaffsOatcake]

(my bold)

 

Facing points on single lines are classifed as being facing for normal traffic, so the connections in the pictures which trail into the lines from the goods yards are not facing points.

 

 

 

FPLs can be used on goods lines too - its mandatory for passenger lines but frequently provided for goods lines, if there is a trailing point which has a main route in the opposite direction its called bi-directional

 

 

You tend to find FPLS on freight lines that have previously been passenger routes or diversionary lines. I know of a few exceptions myself but a general observation is that they don't get fitted.

 

Anyway here's the EFPL at Appleby North in 2006. Think it may been removed when they upgraded the route recently and put intermediate block sections along the route to increase capacity.

[martin_wynne]

Anyway here's the EFPL at Appleby North in 2006.

Many thanks for the pic.

 

Here's a drawing of an older BH design:

 

Thanks to Mick Nicholson for the scan.

 

Martin.

[The Stationmaster]

You tend to find FPLS on freight lines that have previously been passenger routes or diversionary lines. I know of a few exceptions myself but a general observation is that they don't get fitted.

 

It was normal Western Region practice in new work to put FPLs on facing points on most goods lines from roughly the mid/late 1960s onwards, especially if the points were worked by a ground frames. For example FPLs were provided at all the new ground frames installed on the Somerset quarry branches in the 1970s. Some 1960s resignalling schemes did not have FPLs on the point machines on Goods lines but by the 1970s it had become standard practice - even the machines on the trap points of lightly used sidings (such as those provided for occasional tamper stabling) were specified to be FPL equipped in schemes that were developed in the late 1970s.

 

The WR logic was that in the scheme of things the additional cost was marginal but the potential savings (in terms of reduced derailment etc costs) more than justified the additional cost of providing an FPL. But I haven't got a clue about what the other Regions were doing at that time apart from being told that the Southern was doing 'something similar' on point machines on heavily used Goods lines in the mid 1970s and seeing some SR drawings of 1960s work which had included FPLs on freight only connections.