My first 3RS locomotive MTH

You should try running it with all the scale wheels in place. The flanges are bigger than NMRA standards and may run fine assuming you have greater than 042 curves.

Pete

I'm building my layout, so nothing but a test track to run it on. MTH specifies 36" radii curve minimum with scale wheels. I've heard that scale wheels run fine on hi-rail track, but may not navigate hi-rail turnouts.

@Oman posted:

I'm building my layout, so nothing but a test track to run it on. MTH specifies 36" radii curve minimum with scale wheels.

That would be 072 minimum 3-Rail track.

I've heard that scale wheels run fine on hi-rail track, but may not navigate hi-rail turnouts.

Depends on the brand of track. Our layout was Atlas solid nickel silver, with larger more generous curves and Atlas #5 turnouts. Once I modified all the guardrails (raised their hight with styrene shim strips so they were the same height as the running rails) on ever turnout, I had no issues operating many pieces of 2-Rail SCALE equipment, and everything up-graded to Kadee couplers.

If it didn't have shims in it to begin with, you shouldnt need the shims in it with the 3R wheels. If you tried to run it on 2R track with the 3R wheels in it, the flanges may have been too tall and it wasnt making contact with the rails.

You'll need to pull the outboard axle back out cover up the gear box and cut the loop off the front of the truck casting so you can fit a Kadee in there. I usually use a zona saw because it makes less of a mess but a dremel would do it too. 

The scale wheels run fine on the flat top 3R track (atlas, ross, etc...). Sometimes you have to put a shim in the switch frogs so the wheels dont drop in, but most of the time they run just fine. I have run some engines on tube top and they'll cooperate, but I would not think they would do tubular style switches too well.

@Boilermaker1 posted:

If it didn't have shims in it to begin with, you shouldnt need the shims in it with the 3R wheels. If you tried to run it on 2R track with the 3R wheels in it, the flanges may have been too tall and it wasnt making contact with the rails.

You'll need to pull the outboard axle back out cover up the gear box and cut the loop off the front of the truck casting so you can fit a Kadee in there. I usually use a zona saw because it makes less of a mess but a dremel would do it too. 

The scale wheels run fine on the flat top 3R track (atlas, ross, etc...). Sometimes you have to put a shim in the switch frogs so the wheels dont drop in, but most of the time they run just fine. I have run some engines on tube top and they'll cooperate, but I would not think they would do tubular style switches too well.

Out of the box, set for 2 rail, I ran it on Hi-rail track wired as 2 rail, so no issue with flanges. My guess is that the axles that now have traction tires were the ones making good contact and maybe the scale center wheels are no longer touching the rail.

This is a 2 rail scale locomotive with fixed pilots, so nothing to cut. Just add Kadee couplers.

All of my other equipment is hi-rail, so I don't want to modify my turnouts for 1 locomotive.  All my track is Atlas O and MTH Real Trax.

Most 2R, fixed pilot locos need the 3 rail coupler mount cut off the truck for the kadee to clear the truck swinging back and forth while the coupler does not move. MTH uses common truck blocks regardless to what the loco is. But go ahead.... try and put a kadee on it without cutting the loop off. 

I wouldn't cut off the coupler tab. There's only a couple that you might need to do. Even on most of those, as well as most of the fleet, I've cut the KD box instead. KD offers a short box coupler for the tightest versions (743 and 806).

 I see a lot of members have cut off the tabs. So maybe I'm not in the majority. I don't regret my method so far.

Look at the space he has on the model in the OP. No need for tab cutting from where I sit.

Thanks for the input on the 3 rail coupler mount. FYI, this is a FM Trainmaster. I'll put some pics up after I remove the foam protecting the railings.

@Oman posted:

I'm building my layout, so nothing but a test track to run it on. MTH specifies 36" radii curve minimum with scale wheels. I've heard that scale wheels run fine on hi-rail track, but may not navigate hi-rail turnouts.

I've been running MTH locomotives with scale wheels since 2009 on the club Hi-Rail layout and my YouTube channel is full of video. I only have one that can't complete a lap of the primary mainline -- UP Big Boy 4014 because the drivers walk on some uneven track. NONE of my engines have been changed over to hi-rail wheels and I also run scale-wheeled cars in the trains. I'm no expert by any means, but I've picked up a few things.

Track that works in a 3-rail context:

• Atlas-O
• Ross
• Gargraves
• MTH RealTrax, but only tested it in loops.
• MTH ScaleTrax
• Lionel FasTrack, but only tested it in loops. Also note that FasTrack has rounded top rail and O-72 is NOT 36" radius at the centerline (it's a bit tight).

Turnouts:

• Ross 11-degree (#5). These have far and away been the best.
• Atlas #5
• Ross #4 (Don't try a Big Boy through one)
• MTH ScaleTrax #4 (actually a #5)
• MTH ScaleTrax #6

Things I've picked up from running at the club:

• Stuff is going to derail. Find out where and why and fix it. My choice to run 2-rail rolling stock and scale-wheeled locomotives at the club has located bad spots and we've been fixing them so everything runs better.
• Make sure your track is even. Avoid twist as these cause a "high center rail" situation and the locomotive will ride up on the pickup roller and walk off the track .
• Avoid kinks in rail joints. Your six-axle diesels will find these for you.
• For six-axle diesels you don't need the outermost pickup rollers and they'll track better without them.
• Don't even think about running on less than 36" radius (O-72) with a six-axle diesel.
• Use Kadee #805, #740, or #745 couplers wherever possible. You can shave 1/8" off the back of the boxes for six-axle diesels, but I've used #743 short box couplers with success.
• Check your trip pins to make sure they don't hang lower than spec (use a Kadee height gauge). Having them a bit higher than spec isn't a bad thing. This will keep the trip pin from tripping you up on the center rail of turnouts (sorry, couldn't resist).
• Don't couple long cars directly to locomotives unless they have a lot of coupler swing (#746 long-shank).
• Set up a few pairs of transition cars so you can mix rolling stock. Make sure they're properly weighted.
• If you have 2-rail Atlas 89-foot flat cars (they're great), dump the atlas couplers because they're plastic and will flex on you and uncouple under load. Replace them with Kadee #746 (You'll need to drill new 1/16" holes in the spacer to align the box).
• You're in the DMZ between two-rail and 3-rail and you'll start exhibiting 2-rail tendencies like converting freight cars and snagging 2-rail cars of eBay. You may even buy a couple of 2-rail locomotives (Sunset's GE 44-ton is sweet).
• Lastly, one of the coolest things to do is go visit a 2-rail layout, switch over your locomotive and run it under DCC with smoke and sound. The first time I did it, two die-hard MTH critics went out and ordered MTH GE Hybrids.

I've talked too much. Hope this helps point out the landmines.

Thanks Matt

I already have the bug to buy fixed pilot locomotives if possible. All my turnouts are #5 and #7.5 except one O-72 and the curved portion is on the mainline. I tried to avoid it but! I'll have a number of 3% grades as this is an over/under layout. I should have good track work having 1/4" ply on top of the WS risers and inclines.

Go Matt! Go Matt! Go Matt! Go Matt!  

come on over...…  

Matt Jackson"

Whaaa!??

The hypocrisy!!! 

@Oman posted:

Thanks Matt

I already have the bug to buy fixed pilot locomotives if possible. All my turnouts are #5 and #7.5 except one O-72 and the curved portion is on the mainline. I tried to avoid it but! I'll have a number of 3% grades as this is an over/under layout. I should have good track work having 1/4" ply on top of the WS risers and inclines.

The #7.5 frog might be a bit big for scale wheels (they'll dip), but there are a couple of ways around it. With a six-axle diesel, it may not dip because of the extra length and axle on each truck.

The more complicated fix is to make a "point" for the frog. We did that at the club for a Ross #8 curved turnout (60"/48" Radius -- O-120/O-96). The frog gap was so large that some hi-rail equipment was derailing on it. The other thing that will help is to glue thin styrene strips onto the guard rails to push the scale wheels away from the center of the frog. There was a discussion about a year ago on modifying 2-rail turnouts to support hi-rail equipment and we figured that about a 1/10" gap between the guard rail and the stock rail was enough to get the flange in the right place on the frog and allow 2-rail equipment to get through. It's trial and error, but this forum survives on members documenting what they find. We need to put a library together.

Thanks Matt

As much as I would like to go full on 3RS, it's not going to happen. I can't believe I was able to install 2 of those shims. Mind over matter. No matter how much I tremble, this must get done!

Terrific discussion.

To Matt's excellent notes, I add the absolute necessity of ensuring that trucks swivel freely. Early on, as i replaced trucks with 2-rail trucks without checking, I found  that some cars gleefully derailed on any whim. Turned out there was always a small glitch in their rotation. There is a fine line between swiveling freely and flopping.
Cars do need to be properly weighted; I believe the NMRA standard is too conservative: 5 oz plus 1 oz per inch of length, 15 oz for a 40 ft car.  I use 12 oz for such cars.
Trackwork: I run full-scale-length passenger cars, with scale flanges. Like a reverse Diogenes, they hunt for imperfections, especially on curves. I use KDs on swing arms  to adjust car separation to just clear on O-72. Truck swing, especially with 6-axle trucks, can be problematic, so a bit of trimming here, a bit of shimming there works: I am not anal about truck perfection, probably a moral failing.
Re switches: I can back a train of my scale-wheel cars through a facing point (Ross) switch at the Club.

Disclaimer, or admission of cowardice: All my locos are 3-rail, to spare the cost and PITA of adding TMCC to a scale engine.