How Small Radius Can An 0-4-0 Go?

All
The weather has changed. Dropped from the 100's to the 80's. And has triggered the ancient response to begin pestering my Dad to set up the
Lionel 027 Christmas train layout, the trains he began buying for me in 1949 when I was born. He would never comply, until I was in an absolute frenzy, about mid November.
And then, to add insult to injury, we didn't set up the trains, but had to take all the track down the basement to his workshop, and clean it with many "O" steel wool and Varsol (Standard Oils' brand name for mineral spirits) And then, we had to bring the locos and cars down, clean the wheels, and lube the gears and axles with Vaseline and 3-In-One oil. By now I was going absolutely crazy... (: (:
However, my question is, how small radius can an HO 0-4-0 steam engine negotiate well. Like a Rivi B&O "Docksider" The axes are one inch apart. I would like to have a loco like this pull a one (or two?) 34' MDC Roundhouse passenger cars.
I live in a nice old 1935 1300 sq ft house with a small living room. And I have a very nice flat base with side moldings table that would perfectly accommodate a 41" X 41" piece of Homosote. It is new and came from a museum that decided not to use it for a display.
I would like to do something other than putting on a 36" radius circle. I would like to put a winding loop around a town of small buildings around a beautiful 2 ft tall plastic tree that looks like real, and really neat with decorations and lights.
Has anyone else here had experience with small radius HO trains? Could you tell me what has worked for you? I propose to use Flex Track.
Thanks and Very Best Regards,
Robert
Arlington VA
rhsbAThomeATverizonDOTnet
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

The loco will negotiate a 15 inch radius curve. Froggy,
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Robert wrote:

Without a trailing load it would go around something like a 3" radius. The limitation for your project will be coupling the stock together. The limitation for a (passenger) car comes when the trailing bogie is close to right angles to the leading bogie. Take the distance between bogie centers and that will be your minimum practical radius. (per car)

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Greg Procter wrote:

...
Hmm, not quite. Flip your car upside down (the model, that is) and place the two trucks at right angles to each other. Now imagine a line through the center of each truck (parallel to the axles). If the car was on a piece of curved track, the center of the curve would lie at the intersection of these two straight lines. The radius of this curve (at its centerline) is the distance from the straight lines' intersection to the center of either truck; a straight line connecting the two trucks is the hypotenuse of a right triangle, with the curve radius as the legs.
There4, the minimum radius is (1/2 * d ^ 2) ^ (1/2), where d is the distance between the trucks.
At this radius, the force on the trailing truck is straight sideways. Theoretically, a 34' passenger car could be pulled around a 2 3/8" radius curve...but as the curve gets tighter, the pressure of the flanges against the rail increases, and on a curve that tight the wheel would probably climb right over the inside rail instead of following it.
I suggest you experiment. Tack some flextrack to a board and see how tight a curve will work well. I got a train with fairly standard equipment to go around a 9.5" radius HO curve... See this thread: http://groups-beta.google.com/group/rec.models.railroad/browse_thread/thread/c6b5423132de089/cd711c35463a4e39?lnk=st&q=radius&rnum=3#cd711c35463a4e39
Cordially yours, Gerard P.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
snipped-for-privacy@gannon.edu wrote:

http://groups-beta.google.com/group/rec.models.railroad/browse_thread/thread/c6b5423132de089/cd711c35463a4e39?lnk=st&q=radius&rnum=3#cd711c35463a4e39
The minimum possible radius is when the car starts acting like a turntable bridge (diameter of track circle equals truck spacing)!
Dan Mitchell ===========
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
"Daniel A. Mitchell" wrote:

That works for a vehicle with powered wheels, but not for unpowered. Even the theoretical minimum above won't (quite) work because the side forces on the flanges exceeds their guiding force.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Robert wrote: [...]

[...]
The 0-4-0T Docksider will easily run on 12" radius, and has been known to negotiate 6" radius curves. Really!
Actually, with this engine, you should think more about the cars it will haul. Although 34ft cars will negotiate 12" curves, and run well on 15" curves, they look better on larger ones. You may have to increase coupler swing, though, as the back end of that lokey will swing amazingly far to one side as enters a curve.
Rule of thumb #1: use the largest radius curves you have room for.
RoT #2: a simple layout is better than a complicated one.
RoT #3: use easemenst (spirals) leading from straight to curve. This permits smaller radii than otherwise.
RoT #4: run the trains slo-o-o-owly. Less likely to pick rail joints, takes longer to traverse the layout, and looks better too.
Have fun!
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Wolf Kirchmeir wrote:

Many years ago, Varney produced the first "Dockside" (a particular B&O 0-4-0T, with two prototypes) model. It was the ancestor of all the hordes that followed, and Varney had an advertisement that featured a Dockside running around the rim of a HAT. It couldn't have been much more than 6" radius.
Dan Mitchell ===========
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
The problems with small radius curves ends up coupling the loco to the cars. Talgo trucks (the ones with the coupleers attached to the truck rather than the car body) will make the abliity of the train to take small curves a lot easier. If you really want small curves, the 3" radius or so can be done with specially selected equipment. I've seen a train running on a regular hat rim so take that as one possibility. I'd not wear the hat while the train was on the tracks as I can't hold my head that steady but there are those who can for a while. Have fun!
-- Why do penguins walk so far to get to their nesting grounds?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Bob May wrote:

Why do you call bogie mounted couplers "Talgo"?
To me, "Talgo" refers to the Spanish designer and more normally to his design of single axle coach units which hook, one by one over the axle of the preceding unit.to form a low flexible unit train. Nothing in there to suggest a coupler mounted on the bogie!
Regards, Greg.P.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Greg Procter wrote:

Dear Greg: The term's been used that way in model railroading for at least 30 years. (Robert Schleicher uses it in his MODEL RAILROADING HANDBOOK, for instance.) I don't know why, but sometimes with language it's better not to question too much.
Cordially yours, Gerard P.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Greg Procter wrote:

Dear Greg: The term's been used that way in model railroading for at least 30 years. (Robert Schleicher uses it in his MODEL RAILROADING HANDBOOK, for instance.) I don't know why, but sometimes with language it's better not to question too much.
Cordially yours, Gerard P.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
snipped-for-privacy@gannon.edu wrote:

I don't know when it started, but the term was common when I was getting into the hobby over 40 years ago. Likely it began sometime in the mid 1950's, with the rise of cheap ready-to-run HO trainsets.
Dan Mitchell ===========
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
"Daniel A. Mitchell" wrote:

The Spanish Talgo train prototype was reported in Popular Mechanics in 1949. Sounds like someone misunderstood the principles involved.
Regards, Greg.P.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Greg Procter wrote: snip

Long before they introduced the term Tyco to describe their ready-to-run line, Mantua marketed "tyco trucks". These were an early (or perhaps the first) version of truck mounted couplers. In the late '50s they also produced a model of the Talgo train. I cannot give a specific date, but, I believe these two terms may have been combined to produce "Talgo trucks" - a bit of nomenclature which has been with us for well over forty years. I hope this may be of some aid. Thank you. Jerry
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
" snipped-for-privacy@hotmail.com" wrote:

The term "Talgo truck" is purely a US usage. The rest of us call them bogie or truck mounted couplers. I just wondered if there was some technology or logic I had missed.
Regards, Greg.P.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Don't know GP, but the term has been in use for at least 45 or 50 years. You can bet there is some reasonable explanation, but it's been a very long time. Perhaps the Talgo train was built with bogie-mounted couplers. I never use the term myself, but "everybody" knows what it means.
That's just the way it is. Froggy,
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Froggy, @, thepond..com wrote:

The very first Talgo train consisted of bus type bodies on "A" frames, a wheel each side at the base of the "A" and the top point resting at the mid point between the wheels of the next coach. Since then, Mk5 has become more complex with single "axles" floating between bodies to make the whole train bi-directional. Somehow I'm not seeing what someone else saw back in 1948! Perhaps I'm just looking too hard?

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Nope, you're not the only one who is not seeing it. I don't see it either. It's one of those words that everyone uses that makes no sense to me, like friction bearing when what they mean is solid bearing, or wide cab when what they mean is wide nose or crew cab. That's why I never use the word. It doesn't make any sense to me. I always say "truck mounted couplers". One can also say "bogey mounted couplers". I looked up both truck and bogie in my dictionary. They share a common railway definition and are the same thing. It is interesting that people will defend the usage of these words and phrases, even when confronted with the evidence that they are incorrect or meaningless. But Ma, everybody's doing it! Froggy,
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Greg Procter wrote:
>> Nope, you're not the only one who is not seeing it. I don't see it >> either. It's one of those words that everyone uses that makes no >> sense to me, like friction bearing when what they mean is solid >> bearing, or wide cab when what they mean is wide nose or crew cab. >> That's why I never use the word. It doesn't make any sense to me. >> I always say "truck mounted couplers". One can also say "bogey >> mounted couplers". I looked up both truck and bogie in my >> dictionary. They share a common railway definition and are the >> same thing. > > Outside the US they aren't the same thing: - a truck is a single > axled swivelling frame - and also the piece of equipment for carting > sacks and the like.
Or a four-wheel open or flat wagon - a goods truck, or a carriage truck. Common usage on the NSW railway. Elsewhere in Australia, too. And, I suspect, in the UK, if the Reverend Awdry's "troublesome trucks" are any indication. :-)
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here. All logos and trade names are the property of their respective owners.