will a GP-7 fit on a four-foot radius?
WHICH GP-7??? What make??? Did you mean to say a 4 foot DIAMETER? (r1). A 4 foot radius is a 8 foot diameter and most anything will negotiate an 8 ft diameter. Some do not look so good untill you get to the area of 10 ft diameters. So if you will clean up your question someone will respond with the correct answer.
sorry…let me restate my question… will USA Trains’ GP-7 negotiate a 4 ft diameter (R1) ?
Sorry dude. USA Trains requires something on the order of 5-8’ diameter.
traintrax4
As a very loose general rule, about the only thing that will go around a 4 ft diameter and still look good is something in the line of 0-4-0 through 4-4-0 and of course street cars. Looks to me as if it is time to rip out the R1 curves and get some flex track and run out the 9 to 10 ft diameters. Your engine will start to look real good when the curves are 10~12 ft diameters. An added benifit to the larger curves is the reduction in rolling resistance, which will allow for longer consists.
The tightest curves that I will run my trains through is an 8’ diameter curve.
I can still fit a 4-6-0 and a 2-6-2
The USA GP’s will go round R1 4 ft diameter but they grind a bit so I wouldn’t recommend using them for a main line but you’d get away with it in sidings.
would the grinding damage the locomotive?
Yes.
It would mean more wear on the flanges and track but I doubt the drive train would be affected as it is contained within the bogie so effectively two 0-4-0’s, (with a mechanisim usually it’s the gear towers that transmit the drive from the body to the bogie that are damaged by too tight a radius).
I can only really go by my unmodified GP38 which shares the same mech and when I first had it I ran it on R1 quite a bit and it runs fine although I switched to R3 4ft rad when I could.
The same motor block is used in the little mighty moe switcher which is sold to run on 2ft radius so I think the real problem is the swing on the bogie, if you’re going to always use R1 curves you might be able to increase the swing by filing or cutting back part of the bogie or body details to increase the swing but that would obviously invalidate any warranty.
Have you contacted USA at all? Email them and see what they say as they don’t put any minimum recommendations on the website.
email - info@usatrains.com
Paul
thanks for the advice! I have a mixture of R1 and bigger curves, so I will try to contact USA trains.