New form tool for the RMI-25 wheel profile now available

[Harlock]

Allen Models is pleased to announce the availability of the first wheel form tool for the RMI-25 wheel profile, which is backwards compatible with the IBLS draft standards, and much improved.

https://allenmodels.com/wft-1-wheel-form-tool.html

This wheel form tool is made from hardened tool steel using the highly accurate wire-EDM process. This tool is based on the RMI-25 profile, which is 100% compatible with the standard IBLS draft wheel profile, but corrected to provide better tracking and wear properties. It is highly recommended for all 2.5" scale and larger engines, and will work with any locomotive on 7.5" or 7.25" gauge rails, including the entire Allen Models lineup.

The advantages to the RMI-25 profile are as follows:

• The 15 degree taper on the outside edge of the flange and the larger inside radius keeps the flange from making a three point contact on the inside edge of the outer rail and reduces or eliminates the grinding off of the rail head.
  
  The 1/8" inside radius on the flange keeps the wheel further away from the head of the rail, making it harder for the wheel to pick and climb up over the rail.
  
  The slightly deeper flange (1/16 of an inch deeper, or .25" total) decreases the chances of derailment on twisted or uneven track, without interfering with the vast majority of cast switch frogs.
  
  The unnecessary 10 degree radius on the inside of the flange has been eliminated, thickening the flange and preventing climbing on frogs and close-set guards.

Dave Coster of Roll Models, Inc. has made the specifications for this profile available to the wider live steam community free of charge, in the hopes that it will be adopted as a new, backward-compatible standard. The full specifications for this standard are available in this PDF file: http://ibls.org/files/2017/RMI_Railwork ... cation.pdf

This wheel form lathe tool is designed to provide cleanup of a rough-machined profile. Because there is a large contact area, it is recommended that this tool be run at very low speeds (60 - 70 RPM MAX) or hand-turned during the final phases of machining of the profile to avoid chatter on less rigid machines.

[Comstock-Friend]

Mike, does a drawing of the roughed out tread come with the tool???

John

[Harlock]

Mike, does a drawing of the roughed out tread come with the tool???

John

No but that's a good idea. My approach with these is to block out the flange with some chamfering and put the tapered tread in place. that minimizes the work that the profiler needs to do, and yet take care of all the precise curves. The final dimensions are given in the PDF link.

[jeffsmith]

I don't understand this new RMI-25 wheel standard. Those modeling 2.5" scale narrow gauge equipment which mostly used a 26" wheel should know that it would scale out at 5.417". The RMI 5.5" ribbed back castings are too small to get a 26" scale wheel out of them using these new standards.
It scales out closer to a 25" wheel. I guess if you don't care about scale then it OK. I welcome the bigger radius and the larger flange, but RMI needs to rework its pattern to accommodate the new standards and still be able to achieve a 26" wheel diameter.
Concerned Modeler.

Jeff Smith

[Trainman4602]

The height of the flange should not accede .187. Any deeper could cause havoc with the frogs unless your building your own track.

Just what the hobby need some company publishing standards in an already messed up standard.

[jeffsmith]

RMI needs to go over its numbers on its new standards sheet. Dimensions WG and WC don't add up. Both are about an 1/8" off.
Concerned modeler again.

Jeff Smith

[Steggy]

Allen Models is pleased to announce the availability of the first wheel form tool for the RMI-25 wheel profile...

The quarter-inch flange height sounds like a sure way to pick frogs and points. If there is any profile that I would consider "best-case" for most applications, at least with 7-1/4 inch or 7-1/2 inch gauge, it would be that of Tom Bee.

[FLtenwheeler]

Allen Models is pleased to announce the availability of the first wheel form tool for the RMI-25 wheel profile...

The quarter-inch flange height sounds like a sure way to pick frogs and points. If there is any profile that I would consider "best-case" for most applications, at least with 7-1/4 inch or 7-1/2 inch gauge, it would be that of Tom Bee.

I second the Tom Bee profile. It works great.

Tim

[Harlock]

The flange height is only 1/16th of an inch taller than the IBLS spec. This is not a lionel profile. If you have a switch frog with a flangeway depth that isn't at least that much taller than IBLS, what happens when the tread surface of the frog starts to wear? Even your regular IBLS flange would start hitting the flangeway. Also, if that particular spec is an issue, work it down with a file to your preferred height after running the profile tool on it.

The rest of the changes are subtle adjustments to help the wear against the rail and to keep it from riding up so easily.

There is already a good amount of equipment running with this profile from RMI from what I understand. Does not seem to be a problem thus far. And in theory it should save rail wear for clubs, especially on the outside rails of curves, which tend to need replacing first.

-M

[Steve Alley]

Just for those out there that does not know this. The IBLS standard was or has a typo in it. They call out for the radius in the corner of the flange to be .093 this was suppose to be the min. and the max was suppose to be .125. If you work this out the outside wheel dial will be larger and inside wheel be smaller. This gives the truck and all the wheels a differential action like the rear end in a car. wanting to turn in the corner. Having the correct radius also make the wheel harder to raise or ride up the rail. This is why we went to this design. I seen a Locomotive once that had no radius on the wheels it was a 4-6-2 Little engine Pascific. It went two laps around a privet track. We had to stop him and tell him to load up. The track had shavings all over the place. Also his derailments the track was slice with .030 cuts. This is what small radius do. or none. We had to replace the right rail with the left rail and vice versa with the other. Just to say from replacing with new rail. Just two laps and all that work was 4 weekends of working on the track.
Also so many clubs are changing to steel rail. I went to LALS Los Angles Live Steamer in May and notice right away the new steal rail on the up hill section to the west end was slippery. I was losing about 30% less traction than the Alu rail. Clubs are change to the steel rail for less replacement. But the truth is the wheel on our truck and engines are Waring faster. What is cheaper replacing the rail or replacing all your truck wheels. Good for me I will sell more wheels and trucks. But that is not the correct or right way to think about this. Personally I wish we stay with Alu rail.
That's my tow cents worth
Steve Alley

[Steggy]

Also so many clubs are changing to steel rail. I went to LALS Los Angles Live Steamer in May and notice right away the new steal rail on the up hill section to the west end was slippery. I was losing about 30% less traction than the Alu rail. Clubs are change to the steel rail for less replacement. But the truth is the wheel on our truck and engines are Waring faster. What is cheaper replacing the rail or replacing all your truck wheels. Good for me I will sell more wheels and trucks. But that is not the correct or right way to think about this. Personally I wish we stay with Alu rail.

It could be that section of track on which you were slipping at LALS had gotten wetted down by another locomotive. Oily water greatly reduces adhesion, and as you know, steam locomotives are very good at producing oily water.

We have had steel rail on the outside of our mainline curves at Illinois Live Steamers for some time. The steel lasts a lot longer than aluminum, gives us less grief with sun kinks and produces better adhesion, as steel-on-steel's coefficient of friction is substantially higher than steel-on-aluminum. I've seen no tendency for properly machined wheels using materials suitable for the application to wear any faster than on aluminum. If anything, the reduced tendency to slip on steel should extend wheel wear.

Something else to consider is that corrosion of aluminum rail results in a highly aggressive surface, due to the formation of aluminum oxide, a substance that is widely used as an industrial abrasive. Whomever is first to go down the track after a period of no running is going to be the one bearing the brunt of the wear caused by running over aluminum oxide, especially in the curves, and especially if their wheels are made of ductile iron or one of the free-machining steels.

As for RMI's version of the "standard" wheel profile, I think they are wrong, but that's just an opinion, and as you know, opinions are like noses: everybody has one.

[cbrew]

this RMI flange profile is/was intended for the narrow gauge equipment, mainly for looks. the large narrow gauge equipment does look od with a small flange.
that tall of a flange is not needed for the size of rail we use. heck i run scale flanges on all the wheels i turn. the target height is .150. I keep the 10 degrees on both faces ( i have increased this a little on larger wheels with out issue) . I can explain why if anyone cares.
as long as your equipment is designed with enough vertical wheel travel. it will stay on the rails.

as for the steel vs alum rail. yes steel rail will last longer, yes it will cause wear on iron wheels, but i have only noticed this on drivers. we have cars at the club with old wheels that have seen non stop service hauling public for 20 plus years and never had to be turned. i did have to shoe the drivers on the allen american after 3 years on steel rail, but the steel tires have no ware the 12 years they have been on the loco. the ten wheeler had steel tires since the get go. i can all so confirm that alum rail does offer a big jump in traction, even more so with steel tires. but the amount of alum dust on the frame of the locomotive tells me that rail will wear out at fact rate. its fine for home tracks with light service. but no good for clubs that haul public every weekend.

I have also found these profile tools are not steel wheel friendly on smaller lathes, so i just learned to grind custom carbide cutters.
but work great on iron wheels.