Big tie replacement project on the NS mainline in NW Indiana.
What is the expected life of a wooden tie?What about rail? I would assume rail is based on tonnage.
NS Annual report gives their rail a depreciation rate of 2.46% which implies a life expectancy of 40.6 years. Ties are @ 3.25% which implies 30.7 years....both of which seem longer than expected.
Mud Chicken, what are your experiences?Ed
Ed,
The Michigan Central track from Detroit to Mackinac, Michigan ran across my beach at Mullett Lake just south of Cheboygan. When this track was pulled up several years ago many of the ties had "date nails" that were from 1917 to 1930. These ties were good for almost 100 years and at that time were pulled out and resold along with the rails, tie plated, spikes and joiners. The track was a fine construction and the NYC steam locomotives that ran on it were Niagaras and Hudsons.
The New York Central upgraded the rails several time over the last century. The last major rail upgrade was just before the Second World War. When the steel tracks were pulled up and resold some of the railroad ties were taken by local residents for personal construction projects and are still around the community.
I pulled a section of the original rail out of the lake, how it got there I can't imagine. It made a nice keepsake until some local scrapper took it for the steel. When Detroit Mackinac pulled up the track the mountains of ties and rails was hard to imagine. They piled them as locations every ten miles or so prior to disposing of them. It was impressive to see them in such quantities.
There are seveal businesses in America that deal in old and used rail trackage it would be interesting to contact them about the lifetime of railroad equipment.
Doc.
MP173NS Annual report gives their rail a depreciation rate of 2.46% which implies a life expectancy of 40.6 years. Ties are @ 3.25% which implies 30.7 years....both of which seem longer than expected
My friend MC will furnish a more detailed analysis but I shall offer this:
New rail is used to replace older rail on major corridores that have been subjected to heavy and continuous use as established by the GTM (gross ton miles) statistics. Also by the continuous inspections that these high density lines receive from the new hi - rail electronic inspection vehicles.
The rail which has been replaced is further inspected and that which is deemed fit for further use is used on secondary lines, in yards or for industrial tracks. Thus some rail that has been relayed to light use situations may continue to be servicable for many years. I presume the depreciation rate (2.46%) has been established after much analysis of these proceedures.
Some of our rail (actually, a lot of it) dates to the 1920's. I would speculate that it's actually relay, pulled from some place(s) on the NYC when the rail on heavier used lines was upgraded/replaced. It's possible that the rail came from one or several locations, loaded when it was lifted then carried more or less directly to the Adirondack Division for relay.
I've seen stick rail that was welded into CWR, complete with bolt holes intact, and in the not so distant past. In that respect, the rail likely came from all over the place.
I'm pretty sure one could probably still find some NYC ties on the line, although most are approaching sawdust.
Larry Resident Microferroequinologist (at least at my house) Everyone goes home; Safety begins with you My Opinion. Standard Disclaimers Apply. No Expiration Date Come ride the rails with me! There's one thing about humility - the moment you think you've got it, you've lost it...
Thanks for replies....this line is NS Chicago - Elkhart line which handles over 100m gross tons per year. These rails typically see 100 trains daily (50 per track). I cannot imagine these lasting more that 10 years.
Ed
When I got into the railroad business a typical good rail life was 400 MGT (million gross tons NOT miles), today rail lives in excess of 2000MGT are being reported. The gain in life is the product of improved metallurgy (con cast, vacuum degassed melting practice) and improved rail management including the use of friction modifiers and profile grinding.
Good quality hardwood natural growth well treated wood ties are typically believed to have around a 30 year life on average. However there is a great deal of variability about that average. The Forest Products Laboratory did an extensive study on the distribution of lives about the mean. You might be able to find the Forest Products curve somewhere on the net.
When the former C&NW branch between Plymouth WI and Sheboygan WI was pulled up a few years ago (after last running perhaps 15 or more years ago, although the east end was run until maybe four or five years ago) they found that some of the rail was British bullhead rail in 15 ft lengths, which was shipped to Sheboygan via lake schooner in 1858. You read that right. The rail lasted about 120 years. The railroad coordinator for Plymouth WI showed me a short segment he saved. The State of Wisconsin is rebuilding the line. Obviously it was lightly trafficked.
Dave Nelson
dknelsong perhaps 15 or more years ago, although the east end was run until maybe four or five years ago) they found that some of the rail was British bullhead rail in 15 ft lengths, which was shipped to Sheboygan via lake schooner in 1858. You read that right. The rail lasted about 120 years
And that ain't all... did anyone study the railhead profile for wear? Bullhead rail keyed in chairs was notable because you could get four 'wears' out of it before it had to be scrapped (wear, then reverse the length, then turn it over and repeat on the 'underside'). How many years would THAT have allowed?
The numbers you are seeing are strictly for accounting purposes and bear little or no relation to a specific tie or piece of rail in track at any location. Actul life at any location is dependent on a multitude of factors that real life brings to bear there. The accounting figure represents at best an attempt to quantify an average situation across all of the property.
steve14 The numbers you are seeing are strictly for accounting purposes and bear little or no relation to a specific tie or piece of rail in track at any location. Actul life at any location is dependent on a multitude of factors that real life brings to bear there. The accounting figure represents at best an attempt to quantify an average situation across all of the property.
Actually there several well developed and accepted track maintenance planning models that predict track component life in any given situation. Development of thsee models began with some research funded by FRA in the mid '70s and then continued by the AAR's Track Maintenance Research Committee in the 80s. The models were commercialized by several consultants and made available to the industry. The AAR's models even made it across the pond and found its was into BR Research's portfolio (now owned by Delta Rail).
There are two types of models statistical and mechanistic (first principles) but that discussion is for another thread.
Buslist When I got into the railroad business a typical good rail life was 400 MGT (million gross tons NOT miles), today rail lives in excess of 2000MGT are being reported. The gain in life is the product of improved metallurgy (con cast, vacuum degassed melting practice) and improved rail management including the use of friction modifiers and profile grinding. Good quality hardwood natural growth well treated wood ties are typically believed to have around a 30 year life on average. However there is a great deal of variability about that average. The Forest Products Laboratory did an extensive study on the distribution of lives about the mean. You might be able to find the Forest Products curve somewhere on the net.
Presence of water (mud), traffic volume and weight/ axle loads, and condition of the track surface (tamping) are the major factors in the variablity of the life cycle. Also, tie life is affected by the frequency of rail change-outs with spikes, especially in sharper curves. However, if a Pandrol or similar tie plate is used where the rail can be changed by just removing the clips without pulling the spikes, that greatly lengthens the tie life.
There's some schools of thought that the older ties - which were air-seasoned for at least a year, and might still have been from 'old-growth' trees - hold up better than the newer ties from younger trees, and which are 'cooked' in a pressure vessel to remove the water and inject the preservative. I've seen a good many in track (clean cinder ballast, by the way) that were in the 40 - 50 year age range.
Rail in any sharp curve has a greatly shortened life, compared to that in tangent track, even with modern lubrication methods.
- Paul North.
MP173 Thanks for replies....this line is NS Chicago - Elkhart line which handles over 100m gross tons per year. These rails typically see 100 trains daily (50 per track). I cannot imagine these lasting more that 10 years. Ed
50 trains a day on each track at that figure is 500,000 tons = 0.5 MGT per day.
With a rail life of 1,000 MGT, that would be 2,000 days, which is about 5.5 years; at 2,000 MGT rail life, 11 years. So your 10-year estimate is pretty close as a 'rule of thumb' or 'seat-of-the-pants' method.
(+1) to PDN's comments. Predicting tie life is both an art and a science. Put an oak tie in a tangent out here with low MGT and it'll last forever. Put a pine/fir tie in a curve and it's gone in a heartbeat. Some Kansas, New Mexico & eastern Colorado branchlines have 1910-1920 vintage ties still in good shape with the help of a dry climate. More would have survived except for the dust-bowl blow dirt that fouled the cinders and was never plowed. (undercutters are only a critter of the last 40-50 years)....Some ties in what was Santa Fe's CV District (DC&CV Ry.) that were place at Day 1 are still out there (others burned in the great prairie fires of 7 years ago south of Satanta) - You can still find 1913 date nails out on the Cimarron Valley Railway.
There's plenty of old 1880's-1890's rail cascaded out into yards and backtracks now being retired because the OTM has worn out, not the rails. With all the secondhand and thirdhand CWR rail now being cascaded into yards, backtracks and branchlines now that railroads have adequate funds to invest in track along with the shiny toys - who knows how long that bigger stuff will last under light use?
Lightweight switches are often replaced because there is no new source of wear parts like switch points and carbon frogs to plane or machine new replacement parts. Planing mills are hoarding light weight blank stock rails in good condition wherever they can find it.
(a government facility near Denver shut down and was sold off with 90# ARA, RE and ARA-B rail on unused spurs (still had mill scale on them, including unused blank rail) The local planing mills sucked up those piles in a NY second.)
Conversely, there are plenty of places where new rail & ties were not properly maintained which condemned the track to an abbreviated lifespan. (SP was really bad about that because of who controlled the pursestrings and who called the shots - it wasn't the fault of the DE's, roadmasters and track people)
When I worked on the NYC "a few" years ago, we expected 40 years out of a new tie, often had to replace ties that were much newer, and occasionally found much older ties that were good for another 50. There are probably a near infinite number of factors in the life of the tree, the process of converting it to a treated tie, to maintenance of the track structure that would affect tie life.
As to rail, I once saw a piece of U-rail that must have been rolled sometime around the Civil War. It was a section of rail that had last felt 100-ton hoppers rolling over it in the early '70s. That rail had to have been over 100 years old.
ChuckAllen, TX
MP173 (5-5):
The term “depreciation rate” implies an accounting application and so often accounting rules are way different from and not much relevant to widely variant physical operations. Thus, your post facts that you brought in are out of harmony with the inquiry, and is of the likes of ‘What color is invisible?’ Nevertheless, the root of your question is an excellent one, and I think most here at the forum knew what you ultimately meant and have not been sidetracked on technicalities (except me!), and everyone is to be commended for that.
Best,
K.P.
----------------------------------------------------------------------------------------------------------------------------------- K.P.’s absolute “theorem” from early, early childhood that he has seen over and over and over again: Those that CAUSE a problem in the first place will act the most violently if questioned or exposed.
I believe that KP had a photo of a new wooden tie cut in half that showed the treating not fully penetrated.
I am sure what every they use now is "Known to the State of California" not to be as good at what was used 60 years ago..
I appreciate all responses.
Looking at the NS annual report and their depreciation rate for rail, it seemed low, but if the rail is taken out of mainline service and used in sidings and secondary lines, it could reach 30 years (on average). Plus, the NS mainline thru town is one of the busiest stretches of railroad not only on the NS, but in the nation.
My son (who is taking accounting class) and I were discussing the practical application of various accounting functions and the reconsiliation between depreciation rates and net salvage value....while I am not an accountant, I tend to be able to understand it a little. It was truly a great father/son moment....talking about depreciation rates!
Well, another portion of the NS in my area (former NKP Buffalo-Chicago line) still has CWR from the N&W era, rolled in 1974. And, it's on their mainline from Buffalo to Cleveland. Fairly heavy use, fast trains. (Time-table speed for intermodal unit trains is 65mph. I've clocked them as high as 69mph. Just don't tell the local police.....) While not 50+ trains each day, from 1974 to now, that's still a lot of trains... And a lot of gross tons.
Ricky W.
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