Turnouts on the Watercress Line

[Nick Holliday]

Had a fine day this weekend visiting the Watercress Line with grand-children etc.  However, I noticed something that puzzled me, as it was contrary to my understanding of turnout construction.

As I have observed from numerous prototype photos, and Martin Wynne succinctly puts it:

"In the majority of cases the check rail extension length is the same dimension as the wing rail reach length, so that the far end of the check rail is aligned with the end of the wing rail." http://templot.com/martweb/templot_gs.htm

 

This basically means that, since the wing rails almost invariably extend from the sleeper which supports the knuckle of the nose of the crossing through one chair/sleeper, stopping just short of the next chair, (modellers please note) the check rails should stop on the same sleeper, unless there is some reason for them to be extended, such as another crossing adjacent or a sharp curve.  However, on the Watercress Line the majority of the turnouts have the check rail extending an additional sleeper beyond the wing rails, as can be seen in these views taken at Alresford.

 

 

Much of the pointwork at Ropley is arranged similarly. 

 

Is this an aberration on the part of the Watercress platelaying crew, or is this a system that is or has been used elsewhere?  I appreciate it makes no difference to the safety of the track, although since they have used relatively short (five chaired) check rails the far end position is more akin to Victorian standards than Elizabethan, but it looks very odd to me.  I know it's the wrong railway, but even the GWR did it the way I described (See http://www.norgrove.me.uk/GWRtracknotes/R2999.pdf )!

[martin_wynne]

Hi Nick,

 

This doesn't comply with the usual REA standard. But on heritage lines you often find that they have used whatever they can get.

 

The check rails are one timber out of position. The extra length on the far end doesn't matter, but the shorter length at the near end maybe does matter.

 

Where square-on timbering is used, it can be border-line dangerous to get check rails out of position. For example in your first picture:

 

 

On the main road (M), wheels reaching the gap in the crossing are just off the flare angle on the check rail and fully checked.

 

But on the turnout road (T), because the square-on timbering has pushed the check rail further forward, wheels reaching the gap in the crossing are still on the flared part of the check rail and not properly checked.

 

That's one reason why pre-grouping companies preferred the equalized (skewed) style of timbering when check rails were comparatively short. Peter Bedding posted a drawing of an LSWR crossing here: http://www.rmweb.co.uk/community/index.php?/topic/99631-lswr-switches-and-crossings/&do=findComment&comment=1905165

 

I'm not suggesting that turnout is actually dangerous, it may be an optical illusion in the photo.

 

(p.s. Templot moves the check rail accordingly when you change from equalized to square-on timbering.)

 

regards,

 

Martin.

[bécasse]

If you modelled it like that, we would be standing in front of the layout telling you that that wasn't the way the real railway did it.

 

Oddly, I was talking to an old friend last month who happens to have been a very experienced and old school Southern PW man and in the course of a long conversation he happened to mention that the Mid-Hants PW generally fell well short of what he would consider acceptable. You can though get away with a lot when a 25 mph speed limit is in force.

[PhilH]

If you modelled it like that, we would be standing in front of the layout telling you that that wasn't the way the real railway did it.

 

Oddly, I was talking to an old friend last month who happens to have been a very experienced and old school Southern PW man and in the course of a long conversation he happened to mention that the Mid-Hants PW generally fell well short of what he would consider acceptable. You can though get away with a lot when a 25 mph speed limit is in force.

Strange...always reckoned to be one of the better ones. in what way did it fall short?

[bécasse]

Well, I was instantly reminded of the conversation by the two photos of P&C work above. I am fairly certain that he would have had something to say about both, even though, as one of the old-school, he would be more concerned about whether something worked and was safe rather than whether it met some theoretical modern standard. However it wasn't just the P&C work that gave him cause for concern.

[martin_wynne]

he would be more concerned about whether something worked and was safe rather than whether it met some theoretical modern standard.

 

The REA designs for bullhead date from 1925 and haven't changed significantly in 90 years.

[PhilH]

Well, I was instantly reminded of the conversation by the two photos of P&C work above. I am fairly certain that he would have had something to say about both, even though, as one of the old-school, he would be more concerned about whether something worked and was safe rather than whether it met some theoretical modern standard. However it wasn't just the P&C work that gave him cause for concern.

You're being very vague.

 

I've been associated with the MHR for nearly 30 years now and have travelled over 20000 miles up and down the line as a fireman and driver on a variety of locos from diminutive tank engines through Class 8s. I've also been party to tests for mainline locos when we get permission to run at over normal line speed. The latest of these was earlier this year when we ran 70000 Britannia at up to 60 mph after repairs. At no time has anybody, whether associated with the railway or not, expressed any concerns about the quality of the Pway.

 

People seem to think that because a preserved line is just that then everything is set up by 5 volunteers and three dogs. Nothing could be further from the truth. Our line was designed and set up by people whose day jobs spookily were designing and setting up Pway on the real railway.It's the same with our signalling set up, the signalling manager being a senior person in the same job on the real railway.

 

I'll ask again, what are the specific concerns about the MHR. If these are valid then I shall seek answers.

 

We don't play at running a railway, it's big business with safety of everybody at the top of the list.

[martin_wynne]

I'll ask again, what are the specific concerns about the MHR. If these are valid then I shall seek answers.

 

Hi Phil,

 

The specific concern in the OP to this topic is that the check rails in the first pic are in the wrong position with respect to the crossing.

 

Wrong doesn't necessarily mean unsafe.

 

Martin.

[PhilH]

Martin

 

I would imagine that there is a reason for this, it would seem strange if it has been in situ for 30+ years and not been noticed before.

 

My concern with the other post is the inference that the MHR Pway is in someway not up to standard. I believe it is, however if this poster could be more specific then the issues could either be put to bed or resolved.

[martin_wynne]

Hi Phil,

 

Another concern is that those check rails are fixed with spring steel keys. Unless there are check rail spacers and bolts (which I can't see any evidence of), check rails are required to be secured with solid (wooden) keys. The reason is that check rails can be subject to heavy side forces which they must resist and remain in the correct position -- hollow spring steel keys can compress under load and the check rail could move.

 

Your PW dept. are probably aware of these matters, and have deemed the crossing safe for use. It wouldn't do any harm to mention it though.

 

Martin.

[Gary H]

Hi Phil,

 

Another concern is that those check rails are fixed with spring steel keys. Unless there are check rail spacers and bolts (which I can't see any evidence of), check rails are required to be secured with solid (wooden) keys. The reason is that check rails can be subject to heavy side forces which they must resist and remain in the correct position -- hollow spring steel keys can compress under load and the check rail could move.

 

Your PW dept. are probably aware of these matters, and have deemed the crossing safe for use. It wouldn't do any harm to mention it though.

 

Martin.

Having been a NR p-way chappie for considerable years, Martin is spot on.

Steel keys in any check rail is a big NO! Bolts and spacer blocks or not.

Whats worse than a steel key is a 'pan lock' that are pictured, worse than bloody useless in a check rail as they break and crush fairly easily.

Pan lock's also promote rail creep in plain BH track.

[PhilH]

I have no idea, that's outside of what I do or am concerned with. I suppose Ican ask next time I'm up though, what I can say is that obviously we have to and do comply with all insurance requirements, whatever level they're set at.

 

Incidentally I was support crew on a mainline trip ending at another 'big league' preserved railway a while ago. It seems the MHR are not alone in their pointwork techniques.