Kato Mikado pulling power

[mike_lawyer]

Background - I have a Kato Mikado with a PRR L1 Conversion kit installed, along with a traction tire driver installed. 

I installed a 21 inch radius curve and have noticed that I can pull about 30 cars comfortably.  There is wheel slippage however when starting the train from a stop on the curve.  Is this consistent with how one of these locos should pull, or should it be able to pull more?

[randgust]

When I did a drawbar pull test on mine, it beat out every other steam locomotive I owned, every diesel I owned, etc.   The problem is if that traction tire axle gets off rail contact (simple as a switch frog), down it goes.  Very dependent on that tire.

The weight on the locomotive is heavily balanced to the back.  I'm assuming your tire is on the #4 axle, one side only?

It works so well, that despite the huge 'heat sink' pewter boiler on it, I've had cases of the motor getting noticeably warm under near-slip load.  It's giving it all she can.   It's by far the heaviest locomotive I own.

[mike_lawyer]

Yes, I have the traction tire driver in the 4th slot.

[TVRR]

Mine behaves pretty much like Randagust stated and will out pull my Mallets and Challenger. Wish they still had these kits as they were relatively easy to install. 

[peteski]

The weight on the locomotive is heavily balanced to the back.  I'm assuming your tire is on the #4 axle, one side only?

Kato traction tire equipped Mikado drivers have TT installed on both sides.  Same holds true for other Kato steam locos (both American and Japanese prototype) I have ever worked on.

[mmagliaro]

On and off over the years, I've seen anecdotal cases of the Mikado with the L1 kit pulling more like 50, but I'd say your 30 is much more typical.  You can get it to pull more if you add weight, or if you get the pressure of that 4th driver to be just right on the rails, i.e. add like a little chip of tape as a shim in the bearing blocks to push them downward a hair (and I mean a hair - we're talking .003" to .005").  Something like that can make an enormous difference (i.e. jump you from 30 to 50).   But as Randy points out, beware the motor.  By tweaking the bearing blocks and adding weight, it's really easy to get a Mikado to pull more cars than that motor can stand.  With 50 cars on it, it gets burning hot.  That's one of the reasons I swapped in a Faulhaber 1016 + 4:1 gearhead on my I1 2-10-0 made from that Mikado and L1 kit.  Oh... and the drawbar.  Make sure it's completely free and is not exerting any upward pressure on the rear of the engine.

[jdcolombo]

Even with a 21" radius curve, there is more friction on the wheels in a curve than on a tangent.  I have a "regular" Kato Mike with traction tire in the #4 position, and it will pull 25 of my weighted (1 oz. each) cars on a tangent, but only about 16 on an 18" curve.  So I'm observing about a 30% drop in pulling power around that curve. 

BTW, this is true of the prototype, as well.  This is why you hear flanges squealing when a train enters a curve, particularly one considered relatively sharp by prototype standards (and a 21" radius N scale curve would be a very sharp curve on the prototype, exceeding 20 degrees).  The flanges contact the inner side of the rail, causing additional friction.  If you are a physics nut, here's a link for you:

https://www.physicsforums.com/threads/calculating-the-friction-on-a-curved-path.722579/

John C.

[Caddy58]

I run similar equipped Kato Mikados, though they have the GHQ NP W3 Kit installed.

With TT on #4 axle (no shims) they will pull 50 cars on 40 inch curves. So 30 cars on 21 inches sounds very reasonable, I would not expect them to do much more.

Cheers
Dirk

[mmagliaro]

And by the way, if you do decide to add weight and cross your fingers on the motor, don't just blindly add lots of weight in the back over the TT driver.  Balance is very important.  I also have a Mikado with a "W3" kit (it's actually my customised W5 made partly of W3 parts).  I got it to pull 60 cars, up grades, but found that the secret was getting some more weight in the front as well as the back.  A lot of unpredictable forces occur over uneven track, especially up a grade or around a curve.  You need "some" weight on the wheels that actually end up touching the rails, and an engine that starts popping a wheelie (figuratively, not visually) isn't necessarily the best puller, even if those back wheels have rubber tires on them.

[mike_lawyer]

Thanks for all the replies, I agree that about 30-35 cars with 21 inch curves seems to be a good result for pulling power.  I could probably add some more weight to increase pulling power, but I have a small layout (9x4 feet), so 30-35 cars is plenty.