What are the minimum raidus that I can run the following:
DIESELS
Old Atlas F-9 new Atlas SW units
Rivarossi AHM FM
Weaver RS, VO-1000 GP-30
Red Caboose GP-9
All Nation/General Models NW-2

STEAM
All Nation 4-4-0 ,4-6-0 , 4-6-2 etc
Atlas 0-6-0
GEM A-5
Weaver 4-6-2

I know that weaver had blinded center drivers on their engine and that Babbit Locomotive Supply can supply blined center drivers? DO Any of the other manufactuers (MTH, Atlas etc) that make 2 rail offer blinded drivers for 2 rail? Does any one offer a service to blind the wheel sets on steamers?

This could this be a way to run large locomotives on small radius track?

(Holy Hairpin turns Batman !!) Could it this really work???

Both of my A-5's, Gem and LWS will take my tightest curves as will my anachronistic RS-3 - inside of 24". So will my Gem B6 and F-3c moguls for that matter....although the moguls do register audible complaints, I have a few tighter spots that only the 0-4-0's will negotiate as fitting those areas....

My 2 2-8-0's - an H-1 and a scratchbuilt SRR both have blind center drivers and will also tolerate all but the tightest of those same curves...

John--

Most of the All Nation locos with six drivers flanged were spec'd at 36" radius; the 4-4-0 perhaps a bit less. Blinding center drivers on the 4-6-0 and 4-6-2 would allow operation on sharper curves.

It is also possible to get diesels to operate on fairly sharp curves. Diesels with so-called "China" drives (vertical motors on individual trucks) generally can take sharper curves than some models with center-mounted horizontal motors & short driveshafts to the trucks. But diesels using six-wheel trucks can have blind drivers also--generally on the inboard wheelsets to rediuce the rigid wheelbase of the trucks.

An important factor in operation on short curves is the length of locos & cars. Longer equipment requires wider curves to avoid problems cause by couplers binding. KD couplers in KD boxes installed on 40' cars will operate (though maybe not couple or uncouple) on curves down to 24" radius. To operate without binding, couplers need to be aligned above the centerline of the track (given a small tolerance). If a car, loco o tender is too long relative to a sharp curve, its coupler will tend to be close to above or even beyond the outside rail--which could cause a problem. (That's why 3R models have truck-mounted couplers.)

think roller coaster instead of trains:

just use 2 axled single truck (don't use 2 trucks) with short wheel base as in trollies for steam engines as well. throw away the side rods since they would
bind on sharp curves. allow one axle to move side to side of say 1/8 inch to
accomodate sharp curves. if the curve is too sharp, it's not only non-pototypical but ugly with the engline/cars look broken up. but so what! with that single short whl base 2 axle truck, it may turn OK on 12" radius at 300 mph! go go go!!! make sure to use 24" (instead of 1" prototype deep)flanges as well. also, grinding up the inside edges of the rail to make
the rail head as spherical as possible would help but why bother to do dat?
just get 10 gauge copper wire as rails. oops! u need to solder those wires
on top of some hi square bars to keep those 2ft tall flanges off the ground.

come 2 think of roller coasters, it maybe fun to do dat. as u know, train
tracks are basically on 2 dimensional space (flat) while roller coasters
are on 3D track!!! up and down, side to side, up and down, ... sharp sharp
curves and sharp sharp up to down transitions!!! more fun fun fun!!!

Carman,

Not every one has the same desire as you do. Not everyone has a huge space like you do. Not everyone has such a sarcastic whit as you do. Thank God for that.

quote:

Originally posted by carman:
if the curve is too sharp, it's not only non-pototypical but ugly

It's entirely possible to have sharp curves and realistic scenery , just model an interurban line with electric freight motors, there tight radius curves are more realistic than wide curves.

John,

MOst diesels will handle 36 inch radius especially 4 axle ones. AS someone said the china block drives will go around much sharper. Evn 30 inch should be possible. You will begin to get into trouble with the pilots hanging out so far that the couplers will not mate up with following cars and if coupled will cause derailments. In scale model railroading, couplers are usually body mounted, not talgo mounted to the trucks. Surprising as this may seem, that actually gives more reliable operation with longer trains. However, you can get them around as sharp curves.

For the steam, any 4 coupled loco should go around 24-36 inch radius. The All Nation stuff was pretty forgiving, but the pacific I think needed about 42 inch radius as built. I don't know anything about the Weaver pacific, but I would check it out carefully before buying. I had a diecast weaver 0-8-0 and the side rods connecting all the drivers were solid. It did not like 52 inch radius. Most brass models have side rods with joints at each driver crankpin - allowing the wheels to shift sideways for curves. I would also be leery of the Weaver 2-8-0 for the same reason - try them before buying.

Another aside, the Gem A5 is oversize for O Scale. Weaver made a much better model of an A5 more recently.

A friend of mine has a WM 2-8-0 built by Overland that will go around 36 inch radius without complaint and that is a BIG 2-8-0.

I have a number of Old US Hobbies locos and they go around 48 inch easily. These are all Pennsy - 2-8-2 and 4-6-2, 2-10-0 and 4-8-2. The Decapod and Mountain do have blind center drivers. The mike and pacific do not.

There are a number of machinests who do custom work. Joe Forerkalb (I don't think I spelled the name right) does a lot of that and he is sometimes on this forum.