Min Radius for N-Scale PRR T-1

[Anonymous]

I've got an N-Scale Pennsylvania T-1 that I've been scratchbuilding.
I've made it by splicing together two older Concor/Kato 4-6-4 Hudson frames,
after cutting off a section and one set of drivers from each.
I've got the thing mated together with the proper length for the 4-4-4-4 wheel
arrangement.
I've gotten two Sagami can motors mounted in it, with flywheels, and the basic boiler shell fabbed out of brass tube, plus a tender spliced up with 8-wheel trucks.

So, the thing runs great (the old Kato mechanisms always were great!)
I'm telling you all this not to pat myself on the back, but to explain that I've come quite a bit along on this, and have a good-running model almost done.

The problem?
I didn't think about the turning radius. I blinded one of the inner sets of drivers, so I've only got flanges on the 1st, 3rd, and 4th sets.
Even so, this thing cannot make it around an 18" radius curve (which is reasonably broad for N-Scale).

What do you suggest I do? My current ideas are:

a) Blind the other set of inside drivers

b) See if I can grind the frame a bit thinner behind the drivers to allow
for more side-to-side slop. Most other steam models have a lot more lateral slop than these old Kato 4-6-4s did. I'd almost hate to do this, because it is such a smooth precision-running mechanism.

I had already tried making the two halves flexibly joined between the two sets of drivers so the thing could "cheat" around curves a little. This doesn't really help, however, because the whole thing still has to sit under a single boiler and THAT can't flex!

BTW, this problem plagued the real T1 as well. It's a long rigid-frame engine. And it's tough around curves.

Thanks for whatever clever insightful suggestions get lobbed my way!

[jrbarney]

Magliaro,
Maybe you've already considered this, but here goes. Don't know which set the gears are on, but if it's not the 3rd set, you could remove the 3rd drivers temporarily and reinstall the side rods, etc., for a slow speed trial run to determine if removing the flanges on the 3rd sets would improve the minimum radius enough before you actually removed the flanges.
Bob
NMRA Life 0543

[Wdlgln005]

Run the engine on 18" or larger track. Hope you have a Ntrak group nearby.
Try running on the outside rail there.

[Anonymous]

See my original post. I AM running it on 18" minimum radius. My new layout
has that as the sharpest curves, with many curves at 22" or 24".
The problem is, it can't even negotiate an 18" curve.

[ndbprr]

The BLI engine that has all four drivers rigid comes with #2 and #3 blind. The second set of cylinders makes the wheelbase humungous. The Bowser worked the same way the RIvarossi articulateds did and the front set swiveled to solve the problem. If removing the #3 driver flanges isn't enough and you are up to it thinning the frame at #1 &4 would possibly allow some lateral play also. It is a big engine and you have the same problem the PRR did. When the first one was making its maiden run west the head of the PRR was giving a speech saying the first T1 was on the property. Little did he know how correct he was. It had derailed on the curve at the west end of the Pittsburgh station. the curve was later widened to accomodate them.