Axle Load

[FLtenwheeler]

Hi

The members of Ridge Live Steamers have been talking about imposing a maximum axle load. I was wondering what other groups are doing? We are thinking that we would be the 300 lbs per axle range.

Tim

[tburzio]

We don't have any standards at our club for axle loading, and we've never had a problem even with some 2 1/2" equipment. Here is a nice paper on what it takes to determine axle loading, as it seems to depend on a lot more than just the rail.

http://millcreekcentral.com/TrackStanda ... ndards.htm
A properly constructed and installed track section is known to be able to carry a maximum axle loading of 500 lbs.

[Curtis_F]

Tim,

On the full-size roads the axle load is a function of rail weight (height & crossectional area), tie spacing and the weakest bridge/trestle on the line.

What factors are driving the club to have a limit?

Also, I've heard of a few clubs instituting 300 to 325 lbs maximum axle loading to protect their aluminum rail, but I've never heard how these limits were determined. How did the club determine 300 lbs?


Has anyone ever done load testing on Aluminum and/or steel rail?


A little curious,

Curtis F.

[LivingLegend]

Tim:

I posted the following in a thread this past February....

For a point of reference.... LALS specifies the following maximum axle weight loading(s):

3/4" and 1" scale - 200 lbs per axle assembly.

1.5" scale - 425-lbs per axle assembly.

The above axle weights, although called out per scale, actually apply to the track gauge instead. Regardless of scale the model(s) are built to.

In other words: The loading of 425-lbs per axle applies to all equipment using the 7.5" gauge track.... Be it 1.5", 2.5" or 3.75" scale locos/rolling stock.

200-lbs loading per axle would apply to 1", 1.5" (36" gauge prototype) and 2.5" (24" gauge prototype) scale locos/rolling stock using the 4.75" gauge track.

It makes no difference if it's a driver axle, an engine or trailing truck axle, or a truck axle under a piece of rolling stock.

LALS replaced their aluminum rail with steel rail on the 7.5" gauge track around 20-years ago... Give or take. The above 425-lbs/ axle weight loading was/is the same for both aluminum and steel 7.5" rail. Aluminum rail is still in use on LALS's .75" and 1" gauge tracks.

The above LALS standard(s) have served well for handling the weight of locos running at LALS. From Bruce Ward's 1.5" scale 0-4-0 "Invicta", up to David Rohrer's 3-3/4" SRRL 0-4-4 Forney..... Using both aluminum, and the later steel rail.

If you think about it.... The axle loading of a 1.5" scale 2-6-0 is around half of what a 1.5" Big Boy would be. The Big Boy's driver axle loading, based upon a 2000-lbs engine only (no tender) weight, would in the neighborhood 175-lbs each.

LL

[Fred_V]

Hi

The members of Ridge Live Steamers have been talking about imposing a maximum axle load. I was wondering what other groups are doing? We are thinking that we would be the 300 lbs per axle range.

Tim

Tim, i asked Foster about that in '09 because i intended to bring my new engine there this year. he said you had no limit and to bring it on down.

did you fine that my weight did some damage? my axle load is near 500Lb. i ran on our groovy track for the Thomas event for over 200 laps pulling heavy passenger loads with no track damage. polished the rail a good bit!

[hptwin]

How is the axle load measured?
Is the method of determining weight on axles to actually weigh each axle separately on a track scale with the engine weight distributed over the remaining axles through the equalizers as per prototype/engine builder procedure? Or is it to take the weight of the engine and divide by the number of axles? There could be some difference in individual weights but the first method requires a specialized equipment, the second gives an approximation of the loads but is simple I have never heard of even aluminum rail being "turned" or flattened by excessive axle load. I started a 3-3/4" 2-4-4 . I worried about the axle loads but there seems to be a good "track record" for even these large, high axle load locos on both aluminum and steel 1.5" scale track. I had some scale aluminum 1-1/4" high rail produced that looks good as scale 56# rail but it does not seem to be operationally required.

Best regards Mike (hptwin)

[Fred_V]

first method. you need to know how much the actual load is on each axle not by guessing.

[Harlock]

Has any club imposed the limit due to rail wear, or is it mostly the weakest bridge in the link? I talked to a local track owner yesterday and he said he didn't have a limit because there isn't much you can build that will be a problem, even on his aluminum. He's had all kinds of big stuff, K28s and such. But his trestles are low, small and overbuilt, so no problem there.

So my question is, is there really an issue with rail wear or is it primarily bridge loading?

--M

[ccvstmr]

Rail is basically a modified I beam...having an unusually shaped "flange" section on the head of the rail and in some cases a tapered web. Rail support becomes an issue when the load is located where there is no tie underneath to support. Real tie plates can have as little as a 1:40 cant to as much as 1:20 cant...tilting the rail inward. After all, when a real locomotive is limited to 40 tons per axle, there's a slight tendency to push the rail outward. Remember, track spikes are inserted to help maintain gauge...not necessarily to hold the track "down".

Having said that, the weaker link in our model tracks would more likely be the method of rail fastening to the tie. Whether a scale rail plate is used, roofing nails or screws, if the fasteners become loose, the rail(s) could be "pushed" over or worse, rail gauge spread.

When I was doing track work, I used a 1" long #10 sheet metal screw with pre-drilled holes in the wood ties. The pre-drilled hole kept the screw from splitting the wood fibers. The length of screw insured there was enough of the fastener inserted in the material without risk of exposure to the elements. Track life when I stepped aside as chairman was pushing 15 years. After that amount of time, aluminum rail in the curves usually needed to be replaced anyway. Still, we didn't have axle loading restriction. Carl B.

[pwcphoto]

At our club we run aluminum rail and have not had any problem with the larger equipment and heavy loads. In looking at the track construction specs that Tony posted, it looks like we pretty much conform to those specs. shown. Spacing of the ties at 4 inches center to center and the minimum length of the ties at 16 inches seems to work out well. We have 3 large RMI steam locomotives, a Prairie, Sweetcreek and Fourney as well as an RMI 70 Ton diesel which I think is even heavier than the steam engines on a per axle basis. We pull some very large loads with them as can be seen in the photos below. Some of the trains are 8 or 9 cars long, and when fully loaded with not so svelt passengers can weigh quite a bit. Never noticed any problems with the rail compressing or bending related to weight, only normal wear in the curves. We have replaced all of our wood ties with the EPS plastic ties and they seem to be holding up fine.

What kind of equipment are you planning on running where you are worried about axle loading?

[Harlock]

What kind of equipment are you planning on running where you are worried about axle loading?

As for myself I have a project on the drawing boards that is a 4" scale 0-4-0 tank engine from 2ft gauge. It's probably getting to the upper limits there due to the lack of many axles and all the water on board as well.

But Jack's 5" scale tank engine #9 made it around Bitter Creek just fine (with some of the mainline still aluminum rail) so I'll probably be OK.

I'm betting Fred V's ride-in engine weighs about the same as Jacks engine and my proposed engine.

So it would seem that as long as your tie spacing is good, the rail is not a real problem. It's bridges and trestles.

-Mike

[Fred_V]

I'm betting Fred V's ride-in engine weighs about the same as Jacks engine and my proposed engine.

So it would seem that as long as your tie spacing is good, the rail is not a real problem. It's bridges and trestles.

-Mike

i weighed mine when i got to Ridge club in Feb. total weight is just over 2000Lb. with 500Lb. axle loads on 3 axles. that is wet but without me sitting in it.