Large Scale Central

Trolley radius?

General Discussion
#1

The indoor layout has reached the drawing stage.

I am adding a Short run for a trolley. What radius size can I use for g scale trolley?

#2

Tight radii and very interlocking are my thoughts

#3

#4

Doug Arnold said:

What radius size can I use for g scale trolley?

That will depend in part on the configuration of the trolley itself -

  • does it have 2 trucks?

  • what is wheelbase of each truck? what is length between truck centers? how much does each truck pivot?

  • is it a single truck 4-wheeler?

  • what is its wheelbase?

#5

Wear of wheel flanges and railhead will be an issue on super tight curves.

And wrapped up in that will be the effect of friction from those on current draw of motor.

#6

All LGB engines will run on 2 foot radius/4 foot diameter. I have a USA motor block and LGB FRR cars running on a 29 inch diameter circle.

#7

If the trolley is small enough, you can get some real tight curves.

#8

Doug, if you have selected your rolling stock, why not test your minimum curvature?

I’d buy a couple of lengths of that plastic track so you could bend and re-bend and test out some curves. Not just to make it around the curve, but as Forrest states, see how the curve affects the friction… in the simplest test, how much does the loco slow down through the curve? Significantly and you can bet you are adding a lot of stress to the drivetrain and wear to wheels and rails.

Greg

#9

I get dizzy just looking at John’s picture! I like David’s but couldn’t figure how I would bend the rail and the trolley! So I will settle for Greg’s idea! Now I have to find a trolley!

#10

http://www.h-l-w.com/electric.html

Usually we get the equipment and then go for less than the manufacturer’s minimum radius, to avoid wear.

Sorry about that pic…

#11

OMG, someone who follows the maufaturer’s recommendations and doesn’t operate his equipment beyond it’s design specifications. I wish you could talk to several of my customers…One particular mining company springs to mind.

#12

Tangential yet relevant, sort of; when I was modeling HO traction in 1980s it was discovered that Athearn blue-box switchers, the SW7, and Baldwin S-12, would go around 9 inch radius curves just fine and even squeak around 7 inch radius if the phase of the moon was right, so I used those mechanisms for freelance traction creations.

These days it has been discovered that Bachmann’s HO scale 4-axle Fairbanks-Morse something or other and even the GP40 mechanisms will round that same 9 inch radius curve.

Whether they should be doing that 40 hours a week is its own conversation.

Bachmann’s little decades-old HO scale 0-6-0 loco design will take the 9 inch radius but is much happier on 12. Years ago on some forum somewhere someone was asking what minimum radius those 0-6-0 could handle and the Honored Experts were saying to not even attempt to take it coupled to a car around anything less than a 15 inch radius curve, Can Not Be Done. Oh? Really? I posted a video of one of mine towing some unmodified Athearn 40ft foot cars around a 9 inch radius horseshoe curve on my On30 layout fragment, both at low and high speeds in both forward and reverse and doing just fine - and good lord the hate and discontent thrown at me for doing that. Cool. :slight_smile:

#13

There’s a technically correct answer and the practically correct answer… unfortunately often people take the limiting condition to be used as normal operation. Some people can say, ok, I’m pushing it and I accept increased wear… and there’s others that wonder why stuff wears out or breaks when pushed to the limit.

Greg

#14

Greg Elmassian said:

There’s a technically correct answer and the practically correct answer… unfortunately often people take the limiting condition to be used as normal operation. Some people can say, ok, I’m pushing it and I accept increased wear… and there’s others that wonder why stuff wears out or breaks when pushed to the limit.

Greg

Yes, and that is what I deal with in my job. I still have no real good answer to “well it used to be able to do that.”, when “that” was outside of the machine’s specifications.

#15

Greg Elmassian said:

unfortunately often people take the limiting condition to be used as normal operation.

Pretty much the norm on some On30 forums during the years I was on those: newbies would ask the absolute minimum radius that X-manufacturer’s such-and-such could do, then plan their whole layout on that as a standard curve.

Do I have to add that they then wondered why they had nothing but trouble when operating time finally came?

#16

Sometimes the school of hard knocks is the only place certain people learn.

I read these forums for years before I even posted, read every post on LSOL, and this forum too… lots of experience and the chance to avoid the same mistakes.

Greg

#17

Oh yea.

#18

Doug: Find some one with the NMRA Data Sheets from way back. They had the info on Street Car trackage and track layout. If you can’t find it email me and I’ll send you a copy.

Paul Austin