OK, people, I have never seen a discussion purely about the alleged wear and tear on the track and roadbed caused by steam locomotives. I have also heard mention that modern all welded rail mitigates, to a very large extent, the effects of the unbalanced machinery of a steamer. I understand the inability to perfectly balance the machinery of a steamer, but what was the ACTUAL effect on the rails? And is the 135-155 lb. all welded rail in use today strong enough for really big steam? What is the UP's experience with their two steamers with regard to track wear and tear? Facts are preferred, but opinion will be accepted.

It's probably going to be hard to find a lot of facts, since I'm not aware of anyone doing any kind of tests or measurements on modern tracks. It would be difficult to do, short of sending 844 to the FAST track in Pueblo and letting her do laps for a few months, and that's rather unlikely.

The hammering effect of steam at speed is well documented, and that hasn't changed. It's impossible to balance a steam locomotive for all speeds and loads. So you get pounding at certain speeds and loads. One of the worst examples I know of is Hillcrest Climax #10, which has the added factor of having the cylinders be at an angle from the horizontal. This provides a vertical component to the forces, basically lifting the engine up for an instant each revolution. At speeds between about 8 and 12 she hops like a Kangaroo.

I don't think this would have any significant effect given the low frequency of high speed mainline steam operations.

The one factor that is a concern is that railroads no longer widen gauge in curves. Concrete ties do have some give in the resilient fastening systems, but they don't make concrete ties that are gauged to 57 or 57-1/4 in curves. I suppose this could mean more rail wear, but again, the traffic isn't frequent enough to be a concern. The tight gauge could be a concern on very sharp curves, leading to engines with long wheel bases binding up, or in in extreme cases, derailing.

I am asking the question because I read somewhere (I can't remember where) that most wear on rolling stock and locomotives as well as the track itself happens at the rail joints. And that welded rail largely solves these kinds of issues, even for steamers.

Does the UP have any restrictions on where their two locomotives can go? I know that the Challenger is "only" a 3-coupled machine, but does its very long overall wheelbase pose any problems?

The loads caused by out of balance of steam locomotive drivers, usually called "dynamic argument" was actually a gift to the railroad industry. This out of balance results in the steam locomotive applying loads to track and bridges greater that the actual weight of the locomotive. This required the railroads to build these structures to support heaver loads that the actual weight of the trais they carry. Once the steam locomotives were gone the railroads were able to make use of this extra capacity to build heavier locomotives and cars. The heavy trains we see today are a gift from the steam locomotive.

One thing I have heard mentioned is counterweights hitting self-guarding frogs.

-Hudson

I have also heard of station platform clearances being such that the platforms damaged, or were damaged by, valve gear eccentric cranks. (In such cases, probably somebody neglected to check the details before modifying a station platform, or somebody dispatched a locomotive up a line before checking all clearances for that class of engine.)

I know for sure this has happened. I very recently talked with someone who was standing at a platform that had just been rebuilt when the platform was torn to shreds by the first Mallet that ambled by on the first coal drag going past after the construction crew left. He was standing on the platform when it happened (and he had a lot to say about how much it scared him as he ran inside the station). He said the local stationmaster had a local contractor build a new platform and the crew had no idea of the clearances they'd need, they extended it right to the outside of the rail. It was a little station somewhere along the C&O, he couldn't recall the station name after so many years, this would have been during WW2 as he said he was waiting for a passenger train connection while he was on leave in the Navy.

About 30 years ago, when I was trying to put together a version of that "Class I Tourist Railroad" that I've written about, I wrote to Union Pacific about just this question as something to address or answer for a host railroad. I no longer have the letter they were nice enough to send back, but I do recall the writer mentioned that the UP dieselized one division or section of line all at once in the late 1940s--I think it may have been the Oregon Short Line, but I'm not sure--and they found that their expenditures for trackwork went down about 25%. Keep in mind that's for changing a whole railroad over to diesels overnight, and as I recall, it was also a line with a lot of older power that may not have been as well-balanced as later engines would be.

A bit about track and right-of-way maintenance in steam--the extra costs weren't limited to the effects of dynamic augment. You also had to deal with a lot of oil drippings from rods and journals, and even worse was the effect of cinders fouling the ballast on coal-burning roads, required more frequent ballast cleaning. Steam also required a cleaner right-of-way in general due to the fire hazards from sparks. It used to be all that weed trimming and burning was a regular chore for just this reason. Most railroads, particularly coal-burning ones, couldn't tolerate the heavily forested rights-of-ways we see today.

Welded rail goes back a ways, at least to the 1930s on the Delaware & Hudson. I've seen photos of NYC Niagaras running on welded rail as they took on water from track pans. Welded rail reduces maintenance by eliminating all those joints, of course, but one thing that not everyone knows is how much all those joints, all those wheels bouncing on those joints, sponge power from whatever locomotives you're using. I've seen estimates that the change to welded rail was worth as much as an extra 5% in horsepower. Having said that, I still like the sound of jointed rail--but I'm a steam fan, too, and that's almost as impractical in today's environment as well, so what do I know?

The comments about some steam locomotives occasionally being hard on lineside structures reminded me of two stories I've seen, though I can not immediately recall their sources. One involved a Norfolk & Western J 4-8-4, when it was on loan to the PRR for testing. Seems the clearance diagram the N&W sent was for one of the early Js which had multiple bearing crossheads, but the engine that was sent was a later one with Alligator heads and a big, heavy bracket to hold the double guides used with them (No. 611 is like this, by the way). The problem was on a platform track at Union Station in Chicago that had a curve, and the bracket swung out, and took out about two feet of the concrete edge.

The other story was about a Chesapeake & Ohio T-1 2-10-4, which many of us know was the design base for the Pennsy's J-1s. Seems in WW II one of these really huge beasts was put on a troop train and dispatched eastward. Approaching Ashland, Ky., this train was routed into the passenger station, which off the main route on a passenger-only line through the city there. The T-1s had never run there before, nobody had ever thought one would go there before, and nobody checked the clearances between the butterfly sheds and huge, boxy sand dome. Supposedly the T-1 tore down about 30 feet of the shed before the engineer could get stopped!

We've all heard trains go by with some huge flat spots before. Some of these cars when loaded, exert a live weight load of about 71,500 per axle, probably more than most steam engines. I doubt the impact delivered to the rail by a steamer in good condiditon running at a reasonable speed will damage good track any more than a big hopper with flat spots. When called for unit grain trains at KC, sometimes the train would be delayed because of an acoustic type detector east of town, that would detect the sounds of flat spots. The outbound crew would usually have to set those cars out on arrival to be re-wheeled, which usually resulted in a big delay and/or crew swap. Those kinds of flat spots on loads can really shake the ground when they thump by. I guess it still makes sence to over-engineer the infrastructure to accomodate neglected maintenance. It's like standing on the bathroom scale and hopping up and down. You can bounce the needle way beyond your live load weight.

If you are talking about a large engine operating on a line two or three times a year, it's a non-issue.

And yes, modern rail is more than sufficient for even the largest steam locomotive. Remember that "back in the day," mainline rail was usually 112-pound or less. Most sidings and branches were laid with 90-pound, and yard tracks and those around shops and roundhouses were even smaller/lighter.

Two items:
1 -Steam engines ran on much smaller track than 90#. Try 40# and 60# then work up to 90#. Lumber roads were famous for light rail yet, they ran every day with train loads of logs or lumber. 85# rail was a common rail, also. I have removed miles and miles of 85# and up.

2 - flat spots: Sometime in the late 1970's, I was still in Yuma, AZ. when a train, led by a diesel, came into town with one wheel, on a trailing loco, split in half. The other half lay out in the desert between Yuma and El Centro. Over 8 miles of rail was damaged by the pounding of the broken wheel and caused replacement of a lot of rail.