Correct me if I’m wrong guys but aren’t wood ties required to be replaced by concrete on Class-1s and heavy-haul regionals when they rot-out or when new mainlines tracks are constructed?
Here in Florida the entire 351 miles of FEC’s mainline is tied in concrete and has been for over 20 years now. The portion of CSX from West Palm Beach to Miami where a double-track project to accomodate an expanded and more efficient Tri-Rail commuter train schedule was recently completed, was also constructed with concrete ties. Wood ties remain in some sections of the original single-track mainline and on sidings which upon close examination appear to be fairly new but was laid before the double-track project began. Also, North of West Palm Beach which is single-track wood, I’ve noticed random concrete ties where old rotten wood ties have been replaced.
I’m not quoting anything that I’ve read or heard but it seems logical to me that concrete ties with bolted anchors support 132# rail better than wood ties, require significantly less maintenance and last a lot longer, justifying their additional cost over wood ties. Have you ever seen a sun kink where concrete ties exist? I haven’t, but that doesn’t mean it can’t happen, only that it’s less likely to.
I’m sure that on short lines it’s simply not cost effective to switch to concrete given the nature of their business being a “short” line with traffic being limited to one or two short trains a day. But on high revenue regionals and all Class-1s it makes good business sense to use concrete.
I don’t think it’s a requirement, but probably has more to do with soil conditions than anything else. Here in Arizona the Union Pacific is still using wood to replace existing ties, but concrete on all new construction.
IIRC, there was a discussion here a month or so ago, and someone in the know said that the two types of ties cannot be mixed.
The thinking is seriously flawed Ted. If I get the chance, we can pull the comments apart, one at a time, to see what does not hold up under real world scrutiny.
(#1) To start with, two guys with a minimum of tools can replace a timber tie. The same is not true of a concrete tie.
(#2) If a derailment, etc. damages the fastener on a timber tie, you pull the spike/screw, plug the hole and reset the fastener. Aint gonna happen on a precast concrete tie. (And roadmasters don’t have spare P8-11’s lying around just to make repairs…)
(#3) Screws in concrete ties are the exception to the rule. You rarely see them. Railroaders will tell you there has yet to be a satisfactory screw design for track purposes put on the market YET. Suppliers and railroads continue to experiment, especially around turnouts, with screws, plates and OTM that can survive hard service and abuse. Then your trackforces have to have the proper tools to extract the things. This is a big headache, especially with designs no longer made, but still in track.
(#4) Think of timber ties as shock absorbers and concrete ties as piledrivers. Now look at that subgrade under the ballast and think on what it takes to support either. Look at what happens in dry soils, wet soils, sand. And then there’s the headaches with Pac-Trac. Sand is OK if it’s confined, but at laest one retired FEC Ch Eng I know still gets headaches caused by what concrete ties do to even minor fill sections, bridge approaches and concrete-tied ballast sections that degrade good ballast into dust almost overnite.
(#5) What gets you the most bang for your buck? (So the operating department can waste more money on shiny new EMD and GE toys while looking for a shorter return on investment brought on by the cost of fuel…They tend to forget about the fixed plant they run on or give it its due until failure somewhere bites them.)
(#6) Bridges/ dead weight and a requirement to be ballast decked which is not always pra
Most of your points are right on. You are basically trading one set of problems for another. Most track people don’t understand what the problems are with concrete ties, therefore they don’t want to go there.
However, as to concrete tie turnouts, there are more than a few. CN has some I believe and Caltrain has about 60 main line concrete turnouts in 100 route miles of railroad, including #20’s with spring rail frogs that are operated at 50 MPH through the turnout side. Yes, it is a “light” load, but when you slam through the wing with 30 trains a day you are doing more than the BNSF does on their spring frogs on the Trans-Con.
Just thought I would show you all this. This is the website from the Portland Cement Association. and thier role in Transit and Rail. There are some pretty interesting articles in there.
Just wondering if the coal dust that builds up in the PRB has an additional effect, since the carbon has some conductivity associated with it. It looks like another Excedrin headache; number assignment pending (for those oldsters who remember those commercials).
The double tracking of the BNSF transcon between Mulvane, KS, and Wellington, KS, finished last year have concrete ties on the new portion although, all the bridges have wood ties, and the switches have wood. I would assume that in Florida concrete would have a significantly longer life than wood with all the rain and swamp like conditions?
I was curious, I have been told before that the tighter the curve, that wood performs better?
The thinking is seriously flawed Ted. If I get the chance, we can pull the comments apart, one at a time, to see what does not hold up under real world scrutiny
Mudchicken being pretty much accepted as our resident expert on things related to track and plant, you have to pay attention to what he says.
I am guessing , but the message that comes through to me is that, ‘you cannot be all things to all people.’ The same rationale says a carpenter needs more than one hammer, and a mechanic needs more than one wrench. Concrete,prestressed ties have an oobvious place as do wooden ties and even steel ties; each product useful in its special place…
CSX north of DC is just finishing pulling up the run from the Benning (Anacostia) yard to its tie in with the old B&O Main Line and put down wood ties again. No concrete around here that I have seen.
The transition from wood to concrete and back is typically done by installing a group of longer wood ties (ususally something like 10’) between the concrete and the standard wood ties. Every road has their one standards, but you could expect there to be about 10 or so of these longer ties.
This is the same logic used for any transition from a relatively softer track section to a stiffer one such as into a grade crossing, a switch or onto an open deck bridge.
union pac laid new con. ties,ribbon rail,and granite chips 600 miles chicago to omaha. north track that holds the full coal trains eastward. on some switches they use steel ties. composite ties are on lower traffic routes, branches.
NJTransit is currently doing lots of trackwork and a large part of it is installing concrete ties, though only in various spots and some curves I noticed. Most of it by me was simply new wooden ties but further down they tore a whole town’s main street apart to do a whole curve by a station area with concrete ties.
While I’m far from an expert on this subject I’ll try to add what little I know.
In answer to the question posed in the very first message, there is absolutely no requirement to use concrete ties in new construction or when replacing existing ties. Quite the contrary, wood ties are still most commonly used today.
The big advantage of wood ties is lower cost. A few years ago an 8’-6" Grade 5 wood tie cost about $35. Adjusting for inflation let’s say $40 today. I understand concrete ties are a bit more than twice the cost of wood making their cost say $90 apiece. Assuming 3000 ties/mile that’s a $150,000 added cost for each track mile for concrete vs wood. That’s just tie cost alone. If what I’ve heard is true, the higher costs of spring clip fasteners and installation may bring that figure close to $170,000 per mile.
On the negative side, the average life of wood ties is certainly no more than half that of concrete and possibly considerably less. They are subject to longitudinal splits which allows water to get inside causing rot and damage from wood destroying insects resulting in a much shortened life span. There is also a growing concern about the environmental hazards of creosote and the disposition of used creosoted ties. One of the reasons creosote is used as a wood preservative is because it is virtually insoluble in water which makes me think these concerns are more a matter of “political correctness” than a real threat to the environment.
The big advantage of concrete ties is obviously their longer life. Theoretically I suppose a concrete tie could last forever but in reality I think their life span when subjected to the repeated pounding of heavy axle loads on mainlines may average closer to 50 years before they fracture and fail. I know little about this and here I’m just guessing. I have heard that concrete ties can be real ballast crunchers because of their relative inflexibility. This often (may
Not quite. Clinton to Boone hasn’t been done yet. West of Boone Track 1 (the north track) is all concrete to Missouri Valley where the single track begins and the single track is concrete from there to Fremont.
Track 2 is concrete from West Denison almost to Missouri Valley. There’s a few miles just east of Mo Valley that is still wood.
A rumor that went around a while back was that they were going to have to redo a stretch out west that was put in a year or two ago. The ties weren’t holding up like they were supposed to. Don’t know if it’s true, but most of the temporary slows seem to be where there are concrete ties. Mostly soft spots that concrete ties don’t like.
A concrete tie (as used in the corridor) has steel imbeded, a pocket for a pad, and a welded in loop for the spring clip.
The tie is is not straight accross but dished in the center for added clearence.
A Rubber Pad sits in the cast pocket, the Rail on the pad, a Spring Clip to retain the rail, and a rubber pad between the Spring Clip and the rail.
As a train passes, you can see the rail float down and the clips rotate in dampening the impact. Switches do have movable Frogs for high speed crossovers.
Northeast Corridor – Kingston, RI click on photo for larger view
