Im planning to maybe add a trolley to the layout over a staging area. problem is, the shelf is 18" wide which would limit realistically the radii to under 8" or so... is that doable without major re-work on a bachmann pcc or dewitt type car?
Yes, it should be possible. Look at Andy's site.
Wolfgang
Pueblo & Salt Lake RR
Come to us http://www.westportterminal.de my videos my blog
Caveat - I am not familiar with the models the OP asked about. This refers to prototype practice.
Many city trolley systems, especially in older cities, had 'streetcorner' curves in the (HO) 6-inch radius ballpark. They literally went around streetcorners, and commonly rounded reverse 'loops' by circling a downtown block, sometimes through an alley with minimum clearances. For a good idea of how tight the turnback curve could be even in the 'wide open spaces' of an upscale suburb, go to Google Maps and enter Shaker Blvd and Green Road, Shaker Heights, OH. The trolley line (still active) runs down the median of Shaker Boulevard. The carpetbeater shape just east of Green Road is the turnback loop. I doubt that it exceeds 50 foot radius.
Since streetcars ran as single units, the 'carlength of tangent between reverse curves' rule can be put on disregard. Also, the curved sides of streetcar turnouts were built as arcs of the basic curve, so the frogs were cast with the curve integral and stocked by curve radius, not number. Since the street trackage I'm familiar with was built with girder rail (read as continuous guardrails) tracking through even a minimum radius curved frog was not an issue.
To get a carbarn into minimum space, consider a transfer table one car long. The one I saw had goalposts at both ends and wire suspended between them, powered from a nearby pole with the equivalent of a loop of extension cord. (Not commercial power - the cars ran on 500VDC.)
To test the models for minimum radius, build a test rig with 300mm (chord) arcs of incrementally reduced curvature - 18" down to 4" in 2" steps to 12". then 1" - with a carlength of tangent at the outer end to allow you to place cars on un-curved rails. Clip on test leads, and run the car inward on the spiral until it reaches its, "I derail here," point. That will tell you how tight you can make your curves.
Just a few ideas. Hope they've been helpful.
Chuck (Modeling Central Japan in September, 1964 - with a trolley line that uses bow poles)
tomikawaTT Many city trolley systems, especially in older cities, had 'streetcorner' curves in the (HO) 6-inch radius ballpark. They literally went around streetcorners, and commonly rounded reverse 'loops' by circling a downtown block, sometimes through an alley with minimum clearances. For a good idea of how tight the turnback curve could be even in the 'wide open spaces' of an upscale suburb, go to Google Maps and enter Shaker Blvd and Green Road, Shaker Heights, OH. ... The carpetbeater shape just east of Green Road is the turnback loop. I doubt that it exceeds 50 foot radius. ... Since the street trackage I'm familiar with was built with girder rail (read as continuous guardrails) tracking through even a minimum radius curved frog was not an issue.
Many city trolley systems, especially in older cities, had 'streetcorner' curves in the (HO) 6-inch radius ballpark. They literally went around streetcorners, and commonly rounded reverse 'loops' by circling a downtown block, sometimes through an alley with minimum clearances. For a good idea of how tight the turnback curve could be even in the 'wide open spaces' of an upscale suburb, go to Google Maps and enter Shaker Blvd and Green Road, Shaker Heights, OH. ... The carpetbeater shape just east of Green Road is the turnback loop. I doubt that it exceeds 50 foot radius.
... Since the street trackage I'm familiar with was built with girder rail (read as continuous guardrails) tracking through even a minimum radius curved frog was not an issue.
Makes me wonder how the prototype rail, especially when it is extra wide to accommodate the girder rail/groove, could be bent to such a sharp radius. Besides having a device to give mechanical advantage to curve the rail, would there be a need to heat the rail to soften it for bending?
Mark
markpierce -I believe the rail used for city trolley lines was a lot lighter gauge rail than a freight train line. Don't know the exact pound rail used.
I have some 55lb rail that was used in Portage Wisconsin
I did some measurements. I flipped my trolleys over on their backs, turned the trucks as far as they would go, and drew lines on paper parallel to the axles. I did this for both the front and the back. The point where the two lines meet is the center of the minimum-radius circle, where the circle itself is the mid-point of the car.
My Bowser PCC came in at 6 1/2 inches, and the Bachmann Peter Witt trolley at 6 inches.
Since this was a rough measurement with a ruler and not a rigorous test by actually setting up a 6-inch radius curve and running a trolley, it is no guarantee of success. The gears inside might bind on such an extreme turn. But, the trucks make it, and the wheels don't seem to hit the frame or shell at this point. I suspect that an 8-inch radius would work with either of these models.
It takes an iron man to play with a toy iron horse.
With only an 18" HO Scale shelf width -- a traction plan consideration that may help when you determine that minimum radius is that not all layout trackage must be located in a street.
In Johnstown, at the end of a run for the Brills & PCCs, there would be a reverse loop placed on one side of the street, with cindered or bricked roadbed. The street as a state highway, continued beyond town, while the PCC returned onto street trackage for the return trip to center city or the carbarns.
So, a reverse loop would only need to be minimum radius for the tightest part of the teardrop-shaped loop.
Some prototype pics...
Coopersdale Loop: http://davesrailpix.com/john/htm/john120.htm
Franklin Loop: http://davesrailpix.com/john/htm/john124.htm
Ferndale Loop: http://davesrailpix.com/john/htm/john184.htm
Roxbury Loop: http://davesrailpix.com/john/htm/john191.htm
Conemaugh Road & Traction circa 1956
An Atlas turntable would also serve as a prototypical turning device. However, it would be something you'd need to pay attention to and deal with manually each time the trolley got there. A loop, on the other hand, could be automated and let the operator deal with other things.
I'm designing an HO trolley rail down the center of my street and I can't find any tight curve tracks to use. Do I have to bend the track from flex track? Can I buy 6-8-10 radius curves anywhere? Does anyone make trolley track sections imbedded in streets? Thanks.
I bent a single rail of Atlas flex track down to about a 4-inch radius to make the pit rail for a small turntable.
Proto 87 makes girder rail pieces.
http://www.proto87.com/Street_track_for_trolleys_and_trams.html
I have bought some of this and it does look very good, but it's effectively hand-laying the track and there's some learning curve involved. I only used sections of straight and curved rail, no turnouts or crossovers or anything fancy.
This shows some of the rail with their cobblestone street sheets. The sheets came in the tan color. I painted the gray cobbles to get the look I wanted.
Custom Traxx offers Orr girder rail. You'll have to handlay it. Click on "Our current catalog" then scroll down:
http://www.customtraxx.com/
Eric
rancherothe radii to under 8" or so... is that doable
here's a trolly loop at the end of the line
greg - Philadelphia & Reading / Reading