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Level Crossing

Richard S.

Joined: 1-01-91

Topics: 6

Replies: 14

Posted: Tue 29th Dec 2015, 2:19am
Level Crossing

In 2016 I plan to relay our level crossing. I wasn't involved in doing it last time and would welcome peoples thoughts. It needs to take regular use from diggers, septic tanker, the occasional Warship engine. Do I use re-enforcing bar? what thickness concrete? Crossing needs to be about 15 -20 foot long.
 

Replies To This Post

Xz

Joined: 1-01-92

Topics: 17

Replies: 244

Posted: Wed 30th Dec 2015, 10:33am

I think I would go for 4" (100 mm) depth if reinforced, or 6" (150 mm) without. That I consider a minimum, dependant mostly on surrounding ground conditions, and I would make it at least 3ft (1 M) wide preferably more. For between the tracks don't use check rails, but leave the concrete 1/2" lower than railhead, that is much easier to keep clean, just a simple sweep with a brush. Crossing vehicles won't even notice the change of level.

You should be aware that frost can go as deep as 18" so if the surrounds are wet or soft take that into consideration.
 

PeteW

Joined: 1-10-13

Topics: 0

Replies: 21

Posted: Wed 30th Dec 2015, 3:50pm

The design of concrete highways is very dependent on the nature of the underlying ground and the number of standard axles using the road.

I have had a quick look in one of my old design manuals and for your purpose I would go for a 200mm deep slab with A252 mesh top and bottom. Concrete grade 30. I would remove 100mmm of the existing ground and replace it with quarry scalpings thoroughly compacted with a whacker plate.

I agree the width of 1 metre and the detail with the level as described by Xz above.

If you anticipate an exceptionally heavy vehicle going over the crossing I would put down substantial timbers to protect it and help spread the load over the surrounding area.

Pete.

 

Richard S.

Joined: 1-01-91

Topics: 6

Replies: 14

Posted: Sat 2nd Jan 2016, 5:46am

Many thanks for the comments. The ground is free draining, quite sandy with full sized ballast. The builder of the crossing did use check rails (Brank new rail!) which we had to break out and modify as per Xz's description as stones kept getting wedged in the check rail. I'm got replacement 80x80mm plastic sleepers to use and will be using steel rail rather that the aluminium rail done last time. Even so it has lasted about 18 years. I'm also going to use longer fishplates with 6 or 8 holes per side to prevent rail drop at the joint which is part of the problem.
 

Xz

Joined: 1-01-92

Topics: 17

Replies: 244

Posted: Sat 2nd Jan 2016, 1:24pm

Richard, there is no need for sleepers in concrete, just weld a few ties across the rails before the pour.
 

HauteSaoneFrance

Joined: 2-01-14

Topics: 27

Replies: 91

Posted: Sun 3rd Jan 2016, 5:28pm

Apologies for breaking in on this thread, I need to establish 2 or 3 crossings, I'm OK on ground prep and concrete specs, done plenty of that but I was proposing a check rail perhaps with a generous (to make for easy cleaning) gap to prevent any concrete edge breakout. As Xz says no need for sleepers a lot of my track is made up with a transverse flat bar welded to the rail itself at 250 mm intervals to keep it in gauge this would sit on top of a hardwood sleeper but not of course when buried in concrete
 

Xz

Joined: 1-01-92

Topics: 17

Replies: 244

Posted: Sun 3rd Jan 2016, 8:37pm

As Richard says, the problem with check-rails in our scale is stones tend to lodge and cause derailments. The lower centre section has much to recommend it.
 

colinedmondson

Joined: 9-08-09

Topics: 3

Replies: 82

Posted: Tue 5th Jan 2016, 7:32pm

If you want a level road surface and intend to use a check rail I suggest placing a strip of closed cell neoprene foam tape in the groove. It stops stones dropping in but the flanges just depress it. It also helps prevent too much water lodging in the gap in freezing conditions, leading to damage.
 

HauteSaoneFrance

Joined: 2-01-14

Topics: 27

Replies: 91

Posted: Mon 11th Jan 2016, 5:43pm

I like Colin's idea of using a closed cell foam strip for gap filling if using a check rail which will do much to prevent concrete edge break out and eases the set up problems prior to concrete pour day. I prefer to use a motorised screeding beam when laying any concrete.

I'm using a combination of 30 X 12 flat bar and Cromar White medium steel rail, What gap width is recommended?
 

Xz

Joined: 1-01-92

Topics: 17

Replies: 244

Posted: Mon 11th Jan 2016, 6:06pm

I go back to my original recommendation. Check rails are not required. Even with foam filling, stones laying on top can still jam and cause a derailment. Been there, seen it.
 

HauteSaoneFrance

Joined: 2-01-14

Topics: 27

Replies: 91

Posted: Tue 12th Jan 2016, 7:58am

Thank Xz nothing like hearing directly from the horses mouth, if using the lowered centre section then how much lower is advisable?
 

Xz

Joined: 1-01-92

Topics: 17

Replies: 244

Posted: Tue 12th Jan 2016, 9:34am

As I put above, 3/8"- 1/2" is plenty. As long as you can clear the flanges, plus a bit, that's all. Flanges should be around 3/16" (see Standards on here).
 
 
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