Green Line Street Crossings Back to Asphalt?

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Re: Green Line Street Crossings Back to Asphalt?

Postby F-line to Dudley via Park » Sun May 06, 2012 1:36 pm

Is there any reason why asphalt crossings are preferable to concrete? I see concrete used on just about every newer LRT system in the country for grade crossings. You certainly don't get the pothole problems on them that you do with asphalt's short life span. Seems like they could make these last a hell of a lot longer that way and not have the climate-related problems with the rubber surface's slickness in cold/wet conditions.

Other systems do concrete base for their street-running tracks too. I know Boston is never ever going to do that because of noise abatement and (maybe moreso) "we've always done it this way", so Huntington's always going to have the same base. But I don't see why that's a constraint for grade crossings.
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Re: Green Line Street Crossings Back to Asphalt?

Postby Patrick Boylan » Sun May 06, 2012 2:50 pm

I've already posted that I think asphalt's not good unless there's something to protect the flangeway. I'm pretty sure that's why most street rail historically had been girder rail. Concrete tends to crumble differently than asphalt.

diburning wrote:Maybe they're using the wrong type of rubber?

my little informal look at a few crossings in my neighborhood, NJT's riverline, they're bumpy rubber for the pedestrians, that is they have a bunch of dots, like bathtub non slip bumps. When I have a chance to inspect a highway crossing without risking injury I'll let you know those particulars, but the ones I've paid attention to are concrete.
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Re: Green Line Street Crossings Back to Asphalt?

Postby MBTA3247 » Sun May 06, 2012 7:42 pm

The EGE wrote:Page 42: http://www.mbta.com/uploadedfiles/About ... %20CIP.pdf

Green Line Grade Crossing and Track Reconstruction:
The project is rebuilding 7 Green Line grade crossings and track on the B-Line: 2 on
Beacon Street and 5 on Commonwealth Avenue. This project will provide improved
performance and more reliable service.

Whoever wrote that clearly doesn't know where the lines are.
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Re: Green Line Street Crossings Back to Asphalt?

Postby typesix » Mon May 07, 2012 12:06 pm

It's not just the Green Line. On the Fitchburg commuter rail, the rubber crossing at Blanchard Rd/Brighton St in Belmont was replaced with an asphalt crossing last Fall.
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Re: Green Line Street Crossings Back to Asphalt?

Postby jbvb » Wed May 09, 2012 11:34 am

When rubber grade crossings first appeared, back in the 1970s, they were heralded as easier on road traffic, quieter etc. I think part of the improvement was supposed to be that the railhead could be level with the rubber, not protruding above as it is with rigid asphalt and concrete. This was also supposed to reduce impact on the rails from vehicle tires, reducing the amount of track maintenance required. It is interesting to read criticism of the rubber crossings, but I expect a big part of the T's motivation is that asphalt is cheaper in the short term.
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Re: Green Line Street Crossings Back to Asphalt?

Postby diburning » Thu May 10, 2012 4:43 am

I don't see how it;s cheaper in the short term....

What kind of maintenance do they do on the rubber crossings? I didn't think they did any.

I don't see how it would be more cost effective in the short run to rip up something that's already there and replace it with something that won't last.

Maybe there's a problem with the rubber crossings that we don't know about (something major that would warrant some sort of cover-up?)
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Re: Green Line Street Crossings Back to Asphalt?

Postby Arborwayfan » Thu May 10, 2012 8:05 am

T is short of operating cash.

Replacing grade crossings is probably maintenance/operating, not capital.

Rubber crossings are durable but don't last forever. When they fail, they can fail spectacularly, with a whole panel peeling up leaving a sudden hole and hazardous chunks. It would make sense to replace grade crossings on some kind of schedule, rather than waiting for them to fail.

Asphalt is cheaper than rubber.

Is there a chance that these crossings were due for replacement, and the T is saving maintenanance money now by using asphalt instead of rubber, the way a homeowner (or a college or anyone else who owned an old building) might save money now by replacing a leaky slate roof with a fiberglass shingle roof good for 25 years instead of a more costly redone slate roof good for 75 or 100 years.
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Re: Green Line Street Crossings Back to Asphalt?

Postby Disney Guy » Fri May 11, 2012 5:29 am

SM89 wrote:I'm in the Netherlands right now and pretty much none of their tram (light rail) tracks have exposed ties. They are either street running or have grass surrounding the rails. If it can be done here, why can't the green line do it? It looks much nicer and if cost really was an issue, I doubt they would continue to do it here.

New Orleans has (or has had) stretches of track with grass.

But grass has to be mowed, an extra labor expense that is significant for the T.
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Re: Green Line Street Crossings Back to Asphalt?

Postby jaymac » Fri May 11, 2012 6:02 am

Another negative for grass is that it retains moisture and inhibits drainage, shortening the service life of both wooden and concrete ties. Mebbe the Netherlands uses steel to maintain gauge. NOLA has constant drainage issues, so more frequent tie replacement may just be a cost of doing business for that operation.
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Re: Green Line Street Crossings Back to Asphalt?

Postby bbfen » Mon May 14, 2012 8:18 am

Arborwayfan wrote:T is short of operating cash.

Replacing grade crossings is probably maintenance/operating, not capital.

Rubber crossings are durable but don't last forever. When they fail, they can fail spectacularly, with a whole panel peeling up leaving a sudden hole and hazardous chunks. It would make sense to replace grade crossings on some kind of schedule, rather than waiting for them to fail.

Asphalt is cheaper than rubber.

Is there a chance that these crossings were due for replacement, and the T is saving maintenanance money now by using asphalt instead of rubber, the way a homeowner (or a college or anyone else who owned an old building) might save money now by replacing a leaky slate roof with a fiberglass shingle roof good for 25 years instead of a more costly redone slate roof good for 75 or 100 years.


I'd be curious to know why they ripped up intersections that were less than five years old though. Surely the lifespan of the rubberized crossings can't be that short.
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Re: Green Line Street Crossings Back to Asphalt?

Postby Arborwayfan » Mon May 14, 2012 8:42 am

Thanks for that piece of information. 5 years seems pretty short, doesn't it?
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Re: Green Line Street Crossings Back to Asphalt?

Postby bbfen » Tue May 15, 2012 6:08 am

St. Paul's and Kent Street both got the noisy asphalt crossing. This was the last stretch of Beacon to be rebuilt.
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Re: Green Line Street Crossings Back to Asphalt?

Postby Freddy » Tue May 15, 2012 11:02 pm

What the NS and CSX does is go ahead of their Timbering and Surfacing Gang and tear out the 'rubber' ,as we called it, repave the crossing then after the gang comes thru put the crossing
back(rubber) in and repave. Since they do it there's a chance that it's done at other places.
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