Arizona Gandy Dancers

[STRR]

Gentlemen,

Just a quick note to provide a bit of assurance.

Using 12lb. rail in good to new condition with tie spacing at 20" center to center, the safe POINT load is 2016lb./wheel/rail. Thus, each tie/2 rails/2 wheels are capable of bearing 4,032lbs.

The same calculation for 8lb. rail yields 1024lb./rail/wheel or 2,048lbs./tie/2rails/2wheels.

I believe it's good to have a fairly accurate understanding of capacities as you build or plan to build.

Good Luck

[Glenn Brooks]

Certainly 4x6” is much better than 4” x4”. We choose the smaller size in Phoenix because they were available as free material via a donation from a pipeline contractor, and we did not have the available budget, or revenue, to source the 4x6. Last year was the peak spike in lumber prices and at the time, each 4x6x12’ was more than $50 each locally. No discounts to be had anywhere. Outrageously expensive for 300 sticks of wood.

Ideally the track crew will start making 5” x7” concrete ties for phase II and III. (You need more bulk with concrete than wood to hold track screws and resist cracking and breakage).

[STRR]

Hi Glenn,

The quoted figures are for a WHEEL POINT LOAD on any size tie. I can figure out, accurately, the load on different size ties IF it is desired or needed. Actually, a 4x4 and a 4x6 can be able to handle the same load depending on HOW the tie is oriented. A 4x6 "standing UP" with the 4" side supporting the rail is the same as a 4x4. Laying down, with the 6" side up would be capable of handling more. Caveat: Supporting ground structure is extremely important. A 4x6 stood up and properly ballasted, will resist horizontal movement better than if it was laid down. The same tie, laid down will support more weight on soft or muddy substructure.

Paragraphs #2 & #3 on the Tie Spacing explanation page (link in earlier post) will allow more accurate calculations.

[STRR]

On good solid ground/ballast, 4x4 ties on 20" centers, minimum axle center to center 20". Maximum single wheel load is 2520lb. per rail - 5040lb. per axle.
Same parameters using 4x6 ties 6" side up. Maximum single wheel load is 2880lb. per rail - 5760lb. per axle. IF the 4" side is up, the maximum loads are the same as the 4x4 example above.

IF ANY axle to axle distance is less than 20", these load ratings DO NOT APPLY due to rail deflection between the ties.

[Matt.Starman]

Just curious...what on center tie spacing are you guys using?

Matt, I think they are using 20” centers, with 4”x4” ties. I just use the length of my framing hammer + a bit, if Iam driving spikes…

Thanks Glenn!

[Glenn Brooks]

Terry, Thanks for positing and reminding me of your data. Very Good engineering data to have. Our proposed phase 2 work will be a mainline that accommodates heavier trains at greater speed. Sounds like the track crew and maintenance superintendent may wish to assess tie spacing to accommodate higher max loads.

One point of curiosity: do cement ties of the same size make a difference? In load carrying capacity? Iam guessing the additional width of the tie is the key factor driving loading capacity, rather than composition or density of the tie. (So far can’t access your original files, as my iPad does not download PDF’s from this forum software…)

Our initial assessment of cement ties, last winter, suggested we might go with a tie size of 5” x7” x 36 to distribute the load of 5/16” or 3/8” anchors in the body of the tie.

Thanks,
Glenn

[STRR]

Glenn,

Concrete ties would have a slight capacity advantage, I believe. The difference would not be worth the time and effort to calculate the modulus of elasticity per size and concrete strength. AND all of that is beyond my abilities. That's where Doug VanVeelan would have been the man to go to.

My first capacity quotes were the most conservative. The later set of quotes would be the MOST accurate considering tie sizes. The biggest difference between wood and your proposed concrete ties would be the size. Being as the majority (and I say MAJORITY) of the live + dead load is transferred straight downward, the width of the tie will have the most effect on load capacity. Wider is Better.

I would recommend using the next size smaller tie for your CALCULATIONS that would be shown to any inspector, licensing authority, or insurance representative. Make a point in showing them just HOW CONSERVATIVE you are being to maximize your Safety Margin. They'll like that.

Remember: A good practice is to space ties (center to center) equal to, or less than the smallest axle to axle distance of any stock to be used on the line. Like full size railroads, you can use smaller ties, rail, and wider tie centers on the sidings and yard trackage. Save yourself a little where you can. It all adds up.

For your concrete ties, I highly recommend purchasing cement, sand, and gravel aggregate in bulk over buy bagged ready mix. You'll have better control of the concrete strength in your finished product. I also recommend using some rebar in the ties. An economical source is left over/waste rebar from commercial construction sites. Extra rebar is always ordered for onsite concrete pours and has to be disposed of at the end of the job. I have seen 40 yard dumpsters and semi dump trucks of rebar going to the scrap yard. I'm sure a couple dozen doughnuts would get you more than you would need. Might also get you 4x4s from the concrete forms when they tear them down, if they aren't planning on re-using them.

Good Luck
Terry

[ChipsAhoy]

The Crown Jewel of our humble fleet finally out in the bright Arizona Sun!
We now have about 1/8 th of a mile of 12# - 15" track guage laid, (goal is 1260' for this first loop)
I've been trying to talk the gang into double guaging the track to also accomodate 12" guage. That would make our park capable of hosting "N" guage, "HO" guage, "O" guage, "G" guage "4-3/4" guage, "7- 1/2" guage "12" guage and "15" Guage. BUT Alas... I keep getting shouted down!
Are there no 12" fellows around wishing to travel a bit?
Scotty

[Glenn Brooks]

Looks like it’s time to start building the passenger plaza and put this baby on display next to it on a siding with turntable access to the mainline. Move the Wagner and the old time 0-6-0 from front of the museum and put them on the other sidings, next to it. locomotive yard showcase, right at the loading zone.

You’d have an instant attraction to build visitation and ridership!

[Fiddleshay]

We now have about half of the track down and about half of that has been ballasted. We have enough 12# rail, ties & ballast to complete the initial loop. We will need more 12# rail to expand further. Anyone know of any available?

[Bill Shields]

I just visited an anthracite mine in scranton pa that appears to have some laying around that they have little use for these days...or is the northeast USA too far?

[tomc]

Keep an eye on Discover Live Steam web site as they get posting for 12lb. from time to time.

Tom C.