You can do that, and a lotta stuff will run on a 15 inch curve. Some stuff won’t. 18 inches is the HO industry standard, all the makers bend over backwards to get their stuff to run on 18 inches. None of them advertises or admits to running on anything less than 18 inches. The few makers with long rolling stock that needs more than 18 inches will mark the package with the required minimum radius, 22 inches or 34 inches or whatever. Some makers are dumb and don’t mark the box with the required minimum radius. This just leads to unhappy customers. There is nothing the LHS can say to the customer to make him happy. Even refunding his money won’t make him happy, he wanted that piece of rolling stock to run on his layout.
The real meaning of minimum radius, is the size of layout benchwork required to make a 180 degree turn. 18 inch radius requires 36 inches (plus an extra inch or two) to do a 180 turn. 15 inches drops that down to 30 inches (plus an extra inch or two) Most of us want the main line to be a loop so that we can watch a train do several turns about the main line before hitting the yard or stopping at a station, or dropping and picking up freight cars off of sidings.
Well, I got to admit that the Corona virus has thinned out the train shows. But, North Shore MRR club is having one in Wakefield, MA, next Saturday, 3 October. Nur Shrine Center is having a show in New Castle Delaware the same day. There may be life after Corona virus.
As for the rolling stock that needs more than 18 inches, what can I say? If you have the room, go with 24 or 32 inch curves. Many of us don’t have the room. And, most (not all, but most) HO rolling stock will handle an 18 inch curve. The most troublesome rolling stock are the full length (80 foot) passenger cars. And maybe the big auto racks and the 85 foot boxcars. Stick with the 40 and 50 foot freight cars.
Another thing that they fail to tell you is to run a test engine on your layout that is the one that takes the most clearance, I have a doodlebug for mine. In fact I just used it yesterday on my new yard that was coming online, discovered a grownd throw too close to the track.
Although 18"R has been the HO standard for some time, it seems like I see more and more catalog listings and such advising “recommended for 22 inch radius or larger”. A problem you get into is a big engine like an SD-70 or AC-4400 might itself go through an 18"R curve, but have trouble when coupled to a train - especially a string of 55’ or 60’ cars.
I have built my last two layouts, and the current planned layout, with 36" minimum radius curves, and with most curves well above 36", and I still prefer my Athearn and ConCor 72’ passengers cars for their appearance on curves.
I have them close coupled equiped with American Limited diaphragms that touch and stay touching all the time.
I do have some full length cars, Bachmann, Branchline, that have been modified the same way and work fine.
But the shorter cars look so much more graceful on my large curves, like watching real passengers…
As an additional note, I have developed a prefered coupler mounting and a number of simple but effective detailing methods to improve the appearance of these cars.
I don’t go crazy with totaling rebuilding them, just ad and change some key stuff to make them much more “complete” looking.
One day I will have to photo document the process and post it on here.
Any and all of my musings about passenger trains should be taken with a grain of salt.
I have no passion, or even real interest, in passenger train operations. I have never completed an operating passenger train for my railroad in HO or N scale. Maybe someday I will, but until then please do not take my ramblings about the subject too seriously.
When it comes to passenger trains, I definitely have a “Dream Big, Build Small” track record.
