Wheel profile vs. "groovy track"

Discuss park gauge trains and large scale miniature railways having track gauges from 8" to 24" gauge and designed at scales of 2" to the foot or greater - whether modeled for personal use, or purpose built for amusement park operation or private railroading.

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Harlock
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Re: Wheel profile vs. "groovy track"

Post by Harlock » Fri Mar 16, 2018 10:30 pm

A lot of interesting comments here. When a friend built their railroad out of bar stock, I was surprised to find that even the hot rolled material was too sharp. I guess it wasn't crappy enough hot roll, some of the stuff from Home Desperate is practically round :D

I too had thought of some of the same ideas for grinding the inside edge of each rail. I think SteveM's idea of a mounted grinding wheel could work with the aforementioned feeler stop, which I would just rest on top of the rail, but long enough so that when it goes over a joint it still stays consistent with the average top surface of the track. Then some kind of adjustable height. It pretty much just needs to be stopped from digging in when you stop. If you have an electric loco with a good speed control, you should be able to set it to a nice consistent, very slow speed and let it run around the track.

Regarding broad gauging - yes only if you have tighter curves or longer wheelbase engines or combination of both, otherwise you can get away with a consistent gauge throughout. On our 9" gauge 3" scale Mesa Grande Western railroad, there is no gauge expansion around curves, and our minimum curve on the mainline is about 60 feet. Our longest wheelbase loco is a consolidation with blind center drivers, only the front and rear drivers are flanged. (see pic)

Most 7.5" gauge railroads I visit regardless of rail type slightly broad gauge the entire line. The Bitter Creek Western Railroad is 7 5/8 rather than 7 1/2. This helps prevent very large engines from climbing over the rails somehow even on the straight sections. The problem it is fixing is a result of poor wheel profile design on the part of the IBLS draft standard, which actually was trying to show the minimum flange height and radius, rather than the desired flange height and radius. IBLS flanges are too small and the radius too small for conventional radius top track profiles.

Regarding flange to tread radius, if you have a decent radius on the track, then making the radius on the wheels slightly larger will prevent flange wear as the track will find the part of the radius nearer to the tread first and keep it away from the flange. If the wheels are steel and the track is steel with a proper radius, there shouldn't be too much wear in that area.

What can really prevent wear is a properly set up pilot truck. A friend in New Zealand (where all track is essentially groovy track - no affordable profile rail exists over there) recently added a pilot truck to his Kerr Stuart prototype. They adjusted it until the side springs kept the front driver flange 2mm away from the outside rail on a 60ft radius curve, with the result that there should be almost no wear on the front driver over time, just have to periodically freshen up the pilot wheels, which is a lot easier. Previously it was experiencing a lot of wear as it is an 0-4-2 that is used in heavy passenger service on most weekends. Now it is a 2-4-2.

Attached is a picture of the 9" gauge Mesa Grande Consolidation, on a 65 ft radius curve and a side view at a crossing to see the wheel arrangement clearly.
Attachments
17-04-16_mesa-grande-7116_uxga.jpg
17-04-16_mesa-grande-7161_uxga.jpg
San Lorezo Flume & Lumber Co. #2 - "Felton"
Live Steam Photography and more - www.mikemassee.com
Contributing Editor, Live Steam Magazine
Webmaster, Allen Models of Nevada

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Rich_Carlstedt
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Re: Wheel profile vs. "groovy track"

Post by Rich_Carlstedt » Sun Mar 18, 2018 7:32 pm

We built what is called Groovy Track here in Wisconsin 20 years ago It is 7 1/2" gauge track, but we spaced the straight rail at 7 9/16" and made all curves at 7 5/8 " . We have a 90 foot minimum radius on the main line . We cut the the Grooves 3/4 " deep and used 3/8' x 1 1/4" HRS flat Bar.
We started to build a "grinding car" using two 14 inch ScotchBrite wheels ( fully adjustable) driven by electric motors (keep it simple) and carrying a generator. But when we bought the cheapest iron ( over 3,000 feet) we found that it was slightly trapezoidal with a somewhat rounded edge in one corner . This meant strictly keeping that edge on the inside of the track ! and only some of the track needed grinding which was done by hand.
So know the quality of your iron !
We cut over 6,000 western red cedar ties ( kindly advised by Quentin Breen at the 1995 IBLS LA meet) using a radial arm saw (Very Fast !)
The saw had a wobble (Dado) blade to make a groove about .020" smaller THAN THE MEASURED thickness of the purchased iron (!)
Four to six ties were grooved at one time , then reversed and a pivoting bar ( think of a paper cutter where the arm comes down ) was lowered into the groove just cut. The slightly thinner bar was placed exactly at 7 9/16 ( or 5/8") and rigidly held gauge when the radial saw cut the second grooved. The wider ties (which were only used on curves) were stacked as a block and all the ends sprayed yellow in order to be ID'd when laying track. About 1/2 hour before inserting the ties into the rail, put them in a 5 gallon bucket of water. They insert much easier AND the wood fibers bend downward against the rail , which acts like a lock when the tie dries.

Rich

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Fender
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Re: Wheel profile vs. "groovy track"

Post by Fender » Sun Mar 18, 2018 8:47 pm

Another thing I found with groovy track--you don't want to make the ties too short. I there isn't enough "meat" on the end of the ties between the rail and the end of the tie, the top part of the tie will split out.
Dan Watson

rkcarguy
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Re: Wheel profile vs. "groovy track"

Post by rkcarguy » Sun Mar 25, 2018 1:44 am

Thanks for all the info. I'm using 19" long ties for my 12" gage, with 3/8x1 flat bars sunk into 7/16" grooves placed in the ties.
Wood is whatever I can get my hands on for 2x4's, soaked in special sauce:)

rkcarguy
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Re: Wheel profile vs. "groovy track"

Post by rkcarguy » Mon Mar 26, 2018 1:50 pm

Harlock, I think that is a good point. If I shoot for a 1/8" radius on the FB rails, and then go for a 3/16-1/4" flange radius, it will tend to want to center itself without the flanges constantly wearing on the rail, and the radius/radius "contact patch" shouldn't wear excessively.
I'm debating just burning some circles from 1" plate on our new plasma table and having a local machine shop CNC turn them, or welding flanges to 3/4" plate and then finish cut them on the lathe at work.

K. Brouwers
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Re: Wheel profile vs. "groovy track"

Post by K. Brouwers » Mon Mar 26, 2018 9:06 pm

Good day all,
Modern prototype railroads have canted tie plates to angle the track for optimum rail wheel contact. I agree with rounding the corner of hot rolled strips used as rails but would it not also be advisable to cut the grooves in the ties to angle the rail to match the angle of the wheel taper? This is easy to do when the grooves are being cut into the ties.This would give a much larger bearing surface lessening wheel wear. I understand this might not be advisable on a club track with different equipment having different wheel profiles but at a home track this would be easy to do.To alleviate splitting of the tie ends would it not be possible to insert a screw in the end of the tie?

rkcarguy
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Re: Wheel profile vs. "groovy track"

Post by rkcarguy » Thu Mar 29, 2018 8:59 pm

I think it would make turnouts a nightmare to make myself, although it may work well. Not sure what more experienced guys think....

K. Brouwers
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Re: Wheel profile vs. "groovy track"

Post by K. Brouwers » Fri Mar 30, 2018 8:09 am

Good day,
You could make the turnouts the normal way and just grind a radius on the edge of the flat bar. To join the sections a gentle twist could be put in the rail to mate up with the switch and tie plates with a bit of grinding to smooth out the transition on the top and edge radius. You are building in 12 inch gauge so you night consider using 2 or 3" channel for your turnout cross ties building your switches would become a welding exercise instead of a fiddly joinery one. The channel would be nearly the same size as your wooden cross ties so I think the appearance would be OK. This would cost a little more but I think the extra durability would make that a minor concern in the long run.

rkcarguy
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Re: Wheel profile vs. "groovy track"

Post by rkcarguy » Fri Mar 30, 2018 10:52 am

I am going to be running a signal system that will sense the train across the rails, so I cannot have the rails tied together with anything conductive.
I am curious, if I have the radius on the track and the flange radius on the wheels to help center the train on the track, do I need the nearly 3* angle on the wheel on the "tread"? If I just leave the tread flat, it would run flat on the rail with no need to angle the tread or the rail.

K. Brouwers
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Re: Wheel profile vs. "groovy track"

Post by K. Brouwers » Fri Mar 30, 2018 1:08 pm

Good evening,
You could completely insulate your switches from the rest of the track a little bit similar to how model railroads were wired before the modern electronic controls. You blocks would not necessarily need to include your switches at the very least you would still need to insulate your frogs. I would think most trains would be long enough to be detected even with the switch not being on the detection circuit.

Flat wheels have been used. What I think is most important for the riding scales is the proper flange root radius. This has been disused before on the board a search should turn something up for you. no need to reinvent the wheel. :wink:

Happy building
Karel

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NP317
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Re: Wheel profile vs. "groovy track"

Post by NP317 » Sat Mar 31, 2018 9:45 am


rkcarguy
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Re: Wheel profile vs. "groovy track"

Post by rkcarguy » Mon Apr 02, 2018 10:15 am

Thanks for that NP317. A video says 1000 words.

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