Gantlet/Gauntlet Track in the USA

[Colin_McLeod]

The bridge over the river Boyne in Drogheda, Ireland, has interlaced track.

 

http://www.google.ie/imgres?imgurl=http://s0.geograph.org.uk/geophotos/02/30/00/2300019_9e001cae.jpg&imgrefurl=http://www.geograph.ie/photo/2300019&h=168&w=300&sz=1&tbnid=HlQWUJVNORKlWM:&tbnh=160&tbnw=285&zoom=1&usg=__5-nbZpHvX9YFbCx0Fphex1vMKHA=&docid=YJRte-2vHTf8dM&itg=1&sa=X&ei=gTyFUanqKKjW7QbfrYEo&ved=0CJkBEPwdMA4

[Talltim]

Not sure if this is a Gantlet or an extended switch, but it needs sharing anyway

http://rrpicturearchives.net/showPicture.aspx?id=3312277

[shortliner]

Most unusual - and that is one hell of a chimbley too!

[trisonic]

I suppose technically Gantlet or Gauntlet has no crossing (see my earlier photos) whereas that one has. I have no idea but it looks interesting!

 

Best, Pete.

[Glorious NSE]

Quite a fascinating arrangement! Really into 'prototype for everything' territory! 

[trisonic]

Tell you what Tim - post the picture in Martin Wynne's "Handbuilt Track and Templot" area and see what he says.......

 

Best, Pete.

[Adrian Wintle]

It looks like the curve was too tight to put the switch blades any closer to the crossing. It is a very interesting piece of trackwork.

 

Adrian

[martin_wynne]

Another reason in the UK case is to bring the switch points within the 350 yards limit for rodding from a signal box.

 

Martin.

[CraigZ]

A long time gauntlet track existed on the New Haven's Poughkeepsie River bridge across the Hudson River north of New York City.  Originally double track when opened in 1889 it was gauntleted around the 1920s to get the bigger heavier locomotives and freight cars onto the centerline of the bridge.

[BR60103]

When Canadian National built its Toronto bypass (Halton and York subs), the bridge over the East Humber river had gauntlet track. (Or, at least, it does now)

I've only seen this when passenger trains get detoured.

 

CN had a habit of minimal bridge-building when they had to pay for it.  The Toronto bypass is mostly double but bridges over rivers are single. Where the highway people put in an underpass, it was double.  One of these stayed single on double width almost the entire time we lived in Brampton (over 30 years) until someone else (GO Transit?) needed to double the track. The road bridge was between two river bridges -- the original path and the rerouted floodway.

(Sorry -- digression).

[martin_wynne]

Gauntletted (interlaced) track on the Boyne Viaduct, Drogheda, Ireland. (5ft 3in gauge).

 

 

 

Photos used with permission.

[trisonic]

Cheers, Martin.

 

Best, Pete.

[Glorious NSE]

I think that Irish one is fascinating - surely if you're paying to maintain the crossover there then you're already funding two points, putting them one either side of the bridge gives you the same functionality with no additional complexity, and saves you maintainence on two frogs and a whole bunch of running rail...

[Talltim]

I suppose you don't need facing point locks

[The Stationmaster]

I suppose you don't need facing point locks

Which are hardly going to break the bank on motor worked points   (And of course they are there on those points anyway - unless they have started running on the right in Ireland?)

[martin_wynne]

I think that Irish one is fascinating - surely if you're paying to maintain the crossover there then you're already funding two points, putting them one either side of the bridge gives you the same functionality with no additional complexity, and saves you maintainence on two frogs and a whole bunch of running rail...

 

The gauntletted track was introduced in 1932 to avoid building a new signal cabin* at the North end of the viaduct.

 

"the central Pratt truss bridge was originally made of three iron spans that were wide enough to carry two tracks. When the bridge was refurbished in the 1930s, new steel girders replacing the ironworks were constructed inside the original bridge before the iron structure was removed. This allowed trains to continue running throughout the renewal process, however the new bridge was no longer wide enough to carry two tracks. The northbound and southbound tracks were interlaced so that one rail lay between the tracks in the opposite direction, as points and a single track would have required a signal cabin on the north side of the viaduct. When the tracks were relaid in the 1990s, the interlaced tracks were replaced with a single track over the viaduct and points at each side."

 

From: http://en.wikipedia.org/wiki/Boyne_Viaduct

 

I was lucky enough to have a cab ride over the bridge in 1986 when the gauntletted track was still in place.

 

*signal boxes are "cabins" in Ireland.

 

Martin.

[Talltim]

Which are hardly going to break the bank on motor worked points (And of course they are there on those points anyway - unless they have started running on the right in Ireland?)

Doh. It's normally my wife that gets left and right mixed up!

[Glorious NSE]

The gauntletted track was introduced in 1932 to avoid building a new signal cabin* at the North end of the viaduct.

 

"the central Pratt truss bridge was originally made of three iron spans that were wide enough to carry two tracks. When the bridge was refurbished in the 1930s, new steel girders replacing the ironworks were constructed inside the original bridge before the iron structure was removed. This allowed trains to continue running throughout the renewal process, however the new bridge was no longer wide enough to carry two tracks. The northbound and southbound tracks were interlaced so that one rail lay between the tracks in the opposite direction, as points and a single track would have required a signal cabin on the north side of the viaduct. When the tracks were relaid in the 1990s, the interlaced tracks were replaced with a single track over the viaduct and points at each side."

 

Ta - so at the point these images were taken it was kind-of an interim, with the track arrangement from manual signalling days retained under colour light signals?

[dave1905]

Since in any case only one train can occupy the gantlet at a time, and somebody would have to control access, they could have done the same thing with a spring switch on either end and single track between.

 

The spring switch would be set to default to whatever would be the normal current of traffic, left hand or right hand running.  A train approaching with the current of traffic would trail through the switch set against them.  If a train had to exit the gantlet and run against the current of traffic (which would require special authorization in the US) they would have to stop and line the switch manually.  Any other move could be made without stopping to line a switch.   It could be set up as an automatic interlocking (whoever steps on the interlocking approach circuit first gets the signal through the gantlet/single track gets the signal) but that would be more costly for a temporary arrangement.

[martin_wynne]

Since in any case only one train can occupy the gantlet at a time, and somebody would have to control access, they could have done the same thing with a spring switch on either end and single track between.

 

Hi Dave,

 

Spring switches can't be used in facing positions on passenger lines. Facing points on passenger lines must be fitted with facing-point locks, and the lock proved and detected before the signals can be cleared.This is a fast passenger main line between two capital cities -- Dublin and Belfast. The non-stop "Enterprise Express" between these two cities was introduced in 1947.

 

The Great Northern Railway (Ireland) was no mean railway company with a fine engineering tradition at their works in Dundalk. I don't have any details of the 1932 mechanical signalling at Drogheda, but we can be sure the gauntletted track was not installed without proper consideration of all the options. G B Howden was CME of the GNR(I) at the time, a respected engineer with several innovations to his name including the Howden-Meredith wheel which saved several lightly used lines from closure -  http://www.dia.ie/architects/view/4722

 

The semaphore signalling in the Drogheda area was replaced with a modern panel in 1978 -- http://www.geograph.ie/photo/3311532

 

The track over the bridge was renewed as a single track in 199?.

 

More about the viaduct - http://buildingsofireland.ie/niah/search.jsp?type=record&county=LH&regno=13620012

 

A well-known model of the GNR(I) main line: http://www.templot.com/GNRI/adavoyle.htm

 

regards,

 

Martin.

[melmerby]

Hi Dave,

 

Spring switches can't be used in facing positions on passenger lines. Facing points on passenger lines must be fitted with facing-point locks, and the lock proved and detected before the signals can be cleared.

 

regards,

 

Martin.

Somewhat off topic:

There is an interesting arrangement on the CJ (Chemins de fer du Jura) in Switzerland where there are four sprung switches at the dead-end station at Combe-Tabeillon, which has tracks arriving from two destinations.

All trains arrive from one track and depart on the other using a scissors crossing with sprung points. It means no external operation is needed and trains are automatically routed the correct way.

 

Cheers

 

Keith

[The Stationmaster]

 

 

Spring switches can't be used in facing positions on passenger lines. Facing points on passenger lines must be fitted with facing-point locks, and the lock proved and detected before the signals can be cleared.This is a fast passenger main line between two capital cities -- Dublin and Belfast. The non-stop "Enterprise Express" between these two cities was introduced in 1947.

 

regards,

 

Martin.

Still O/T (sorry) but just to round out this area we can of course have self acting points but, as Martin has said, they must have a facing point lock.  Here is an example of the design developed by BR for use on rural lines although this was is on the privately owned Torbay &  Dartmouth Railway.   On the national network many of these have now been replaced by ordinary point machines (not trailable) due to difficulty in obtaining spare parts.

 

The first pic shows the point in its normal lie, for left hand running - the grey box at left is the detector for signalling circuits to prove the point is shut and locked for facing movements while the operating mechanism is in the centre of the four foot.  The second picture shows the mechanism opened opened with teh hydraulic cylinder at right and an emergency operating handle inserted at left.

 

 

[martin_wynne]

Hi Mike,

 

Thanks for that. Can you explain how it can be trailed while the facing-point lock is engaged? Or am I missing something?

 

regards,

 

Martin.

[The Stationmaster]

Hi Mike,

 

Thanks for that. Can you explain how it can be trailed while the facing-point lock is engaged? Or am I missing something?

 

regards,

 

Martin.

I'm not sure exactly how they work Martin but it is simply as a result of flange pressure as a train trails through them which causes whatever creates the lock (which I think is exerted by hydraulic pressure?) to release thus allowing the point to move and hydraulic pressure then forces the switches back as the train clears.  Regrettably I can't find any technical references for them at all.

[martin_wynne]

I'm not sure exactly how they work Martin but it is simply as a result of flange pressure as a train trails through them which causes whatever creates the lock (which I think is exerted by hydraulic pressure?) to release thus allowing the point to move and hydraulic pressure then forces the switches back as the train clears.  Regrettably I can't find any technical references for them at all.

 

Thanks Mike. But I'm a bit puzzled. Isn't that simply a hydraulic version of a spring switch? How can the switch rail be described as locked against the stock rail if flange pressure can open it?

 

Martin.