How is curved track laid?

[Anonymous]

[8D]

I live next to the Alameda Corridor in Los Angeles I was I curious to know how curved track is formed? Is it fashioned out in the field or is it pre-fabricated before it is laid? Thanks for the info.

[corwinda]

I know it's laid in the field, but not exactly how.

[Anonymous]

QUOTE: Originally posted by M.W. Hemphill
[The stuff is not like model railroad rail. It's almost as flexible as a wet spaghetti noodle. Heavier, though.

Almost, but not quite, true (sorry to burst your bubble, Mark, but I know what you're saying).

For general RR applications, where the rail length is significantly greater than the cross-section and the curves are gentle, it's a wet noodle and it will go where the equipment puts it. Big, powerful, heavy equipment, by the way--if YOU try to move it it ain't goin' nowhere[:D]

But for tighter radius applications, like subway/urban rail/ LRT and historic trolley systems that get into curves as tight as 30' radius (110' for LRT is standard), it won't bend like that and it is just like model railroad rail, only even stiffer. It's the same rail in most cases--110-112# RE CC, sometimes venturing into the 130-136# class, although girder rail is also used. For that tight radius application there are special portable rolling machines that will bend the rail to the desired radius without damaging it. This saves the track contractor the excessive cost of buying and shipping what would amount to a lot of very LARGE pieces of special trackwork (imagine putting a 112' or 108' rad curved rail on a trailer!) and allows the rail to be field-curved and then installed on the ties, concrete roadbed with pads, or whatever.

Occasionally this technology finds its way to a full size RR, but with increasing car and locomotive lengths, you see is almost exclusively on these other applications.

[csxengineer98]

it comes in pre made pannels in what ever degree radiuse curve you want... or you can use flex track...just flex it to the curve you want..and tack it down to the roadbed...
oh...im sorry..you wanted real track.... real track is layed down by putting the ties down to the degree of the curve needed..and as the rail is installed...it is slowly bent into a curve...
csx engineer

[Anonymous]

QUOTE: Originally posted by csxengineer98

it comes in pre made pannels in what ever degree radiuse curve you want... or you can use flex track...just flex it to the curve you want..and tack it down to the roadbed...
oh...im sorry..you wanted real track.... real track is layed down by putting the ties down to the degree of the curve needed..and as the rail is installed...it is slowly bent into a curve...
csx engineer

Yeah, and it takes one heck of a spray bottle to glue down the ballast[}:)][}:)][}:)][}:)]

[Modelcar]

drephpe....Finally.....I ask that question way back about the street running systems that must negotiate 90 degree turns into streets, etc....HOW...the curves are formed....And finally, you really bring it to light....! Thanks.
But how did the street running systems do it back in the 20's and early 30's when building or replacing rail as such....Did that equipment exist then...?

[Modelcar]

...On street running systems: I dug up an old picture of streetcar tracks as they were being installed in the streets here in Muncie years ago and it shows an intersection with at least {2} 90 degree turns and the rails on the ties, etc....It all looks so sharp and it really made me wonder how those curves were installed so sharp with out "kinking" the rail, etc.....The street material was not installed yet when the pic was made and the rails are on the ties and sitting high with nothing [such as ballast around them to hold it in place.

[mudchicken]

In th bad old days, fire, muscle and a post strategically placed did wonders.

[tree68]

QUOTE: Originally posted by mudchicken

In th bad old days, fire, muscle and a post strategically placed did wonders.

Sherman's Neckties - May not have been 130# rail, but Gen Sherman's troops managed "track" radii in the range of around a nearby tree....

[Anonymous]

[:D]

Thanks Guys,

I appreciate all the information that you have supplied regarding the practice of laying curved track on a "Class 1" railroad.

Sincerely,
Jonathan

[Modelcar]

MC....I can appreciate what you are saying but just looking at those old "radii" curves and how constant most were, it's difficult to understand how fire and muscle managed the curve so constant....I realize it was done some how and of course modern equipment did not exist when most of the street running systems were put in place.

[Modelcar]

...Wasn't their another rail turned on it's side to keep the flange area space clear that would have to have been shaped too.....

[Anonymous]

"Modern equipment" isn't required. The main difference between what they had when the railroads were built and now is that now they are controlled with joy-sticks, electronics and hydraulics. Back then it was foot pedals, hand levers, and mechanical brakes and clutches.

The railroads have always had the equipment they needed to do the job. If they needed to lift an engine back on the tracks they had a crane that could do it.

As for bending rails you can do it by hand with some chains and jacks. You only need to get close and you can spring it the rest of the way, or back a little, and spike it down.

[Modelcar]

....Yea, steam cranes that could lift a hundred tons or so....Saw them work. But bending that rail 90 degrees around a street intersection for a street running traction Co.....It sure makes me wonder how they got the curve bent into a constant radius curve...By hand methods.

[Anonymous]

Steam cranes that could lift what had to be lifted in actuality. They had ones big enough to raise a Big Boy that derailed and was laying on its side. They may have used two or three. Those railroaders are pretty clever.

As for bending rail, here is how they do it in Wales.

http://www.whr.co.uk/civils/2000sbash/

I suspect it isn't too much different here.

[mudchicken]

dgwicks:

Used to be pretty clever...Now they have dumbsized down to "starving and stupid" and pay somebody else to do the thinnin'[:-^][:-^][:-^]

A trusty Jackson 6700 or Canron Mk-4 can make it look pretty! (Can't say the came about most Cat-09's and their Prussian cousins....)

[Anonymous]

And just in case you want to bend some rail yourself ...

http://www.aldonco.com/catalog_category.asp?sec=3&cat=77&subid=77#

The ones at the bottom of the page will handle up to 140# rail!

[Anonymous]

QUOTE: Originally posted by Modelcar

MC....I can appreciate what you are saying but just looking at those old "radii" curves and how constant most were, it's difficult to understand how fire and muscle managed the curve so constant....I realize it was done some how and of course modern equipment did not exist when most of the street running systems were put in place.

How They Did It (by V. Frankenstein??)

This will probably be interesting to you guys who are asking the traction questions, and may surprise some of you:

This is quoted from my copy of the ICS Reference Library for Electric Railway Systems, published in 1908 (!!) (page 56 of Line and Track):

"Street-railway curves are always designed by the radius, in feet, at the center. Long curves of light rail are sprung in, as a rule; that is, the rail is pried over with a bar and spiked into position, the paving being relied on to keep the track in place...On curves of heavy rails and moderate radius, a portable rail bender should be used, while shorter curves should be bent to a templet with a power bender" (my emphasis).

"Light" and "heavy" here refer to rail weight.

In some cases they did lay an adjacent rail sideways for a flangeway, particularly on curves where girder rail was not used. They bent it the same way. Keep in mind, though, the low-end job embodied just laying the one rail, dumping the asphalt in and (modelers, take note--there's a prototype for everything!) running a car through there while the asphalt was soft to cut the flangeways in it with the wheels. Sometimes today this is still done. They would also lay bricks or cobblestones and leave a flangeway, filled with sand. Then there's the St. Charles line in New Orleans, where they laid the rail, dumped in dirt and planted grass over it! When they rebuilt it a few years ago, they did it the same way, but with a layer of fabric over the ties. Ans for those of you who haven't been there, it has grass on both sides, between and up to the rails once it gets in the median of St. Charles St.

Keep in mind our ability to move and bend big, heavy things with machinery goes back a lot further than 1908, which is in the heyday of the trolley. We just changed the power source from steam to electricity or internal combustion and got more sophisticated with controls and materials. But we bend big things today essentially the same way we did then, and with power equipment.

Just goes to show you that technology often goes back a long way.[8D]

[Modelcar]

drephpe and dgwicks and Mark....Thanks for the effort to find good info on the subject of light rail and bending same.....Interesting. And by the way....It seems to me: Anyway it's done it looks like HARD work.
Yes, often in cities and towns in Pennsylvania, my home area...the area between the rails was paved with paving bricks....but in most cases it appeared to have a rail of some sort turned on it's side to define the flange space.

[Anonymous]

I have a loosely related question: how is rail cut? I'm assuming that rail must be cut, so that switches can be even, and to make interlocking diamonds.

Thank you in advanve for any help.

See you around the forums,
Daniel Parks

[Anonymous]

NOT with a torch!!![tdn][tdn] That damages the rail's metal structure, causing catastrophic failures (if I recall right, that's what caused the fatal derailment of ATK 21 near Marshall TX a few years ago--a torch cut on some new German rail).

Generally you cut it with a rail saw, which is a power rotary saw with a special 14-16" (usually) untoothed abrasive blade that will not damage the rail's structure when it cuts through. Here's a link to a spec sheet on one of the many available on the market:

http://www.matweld.com/00800A.htm

[Anonymous]

Dear drehpe,
Thank you very much.

Sincerely,
Daniel Parks

[Anonymous]

Daniel--

You're quite welcome. Glad I could help.

[Kozzie]

Two birds with one stone! Rail bending and cuting info in the one thread! [:)]
Good Stuff![:)] Thanks everyone for the info - very good reading! [:P]

Dave