Having just completed scenicking a large hillside in the corner of my layout behind the roundhouse, I decided to stage some pictures for Weekend Photo Fun. I put a string of full length passenger cars on the inside curve and was going to put a freight on the outside curve. While backing the freight into position on the curve, I was surprised to see it got hung up in a deep cut. On further examination, I discovered the passenger cars had enough overhang to just clip the cars on the outside curve. I had laid this track over 4 years ago and never had a problem but apparently this is the first time I had the long passenger cars inside another train on that curve. I had tested that curve by hand pushing my longest equipment throught it on both the inside and outside track and was satisfied that I had enough clearance. I have 2 inch track centers which I thought would be enough with a 30 inch inside curve radius but apparently, at some point in the curve, it is a little sharper than that.
After spending the past month working to scenic that hillside, relaying the track is not an option I am going to consider. The double track main passes through a deep rock faced cut and I am not about to tear that out and start over. I can live with the inconvenience of not running a train around the curve on the parallel track when the full length cars are on the inside curve. It is definitely the lesser of two evils.
You’ve hit one of the Principle Rules of MRR - It won’t show up until the glue sets…
In consolation one thing that happened with the real RR was that as stock got longer/bigger they had to make easements. Quite often they completely re-routed for a few miles. I think that the SP route over the Rockies has several examples. (Where they could they would take the opportunity to ease the grades at the same time).
All you need to do is ensure that the long cars only run when the other road is clear. This is what the reall RR would have done through the route that they were going to replace while they waited for the new work to be completed.
One thing that might have contributed to the problem was that both trains were backed into the curve which might have increased the amount of buckling. I’ll run some further tests later to determine if I get the same result when the trains are moving forward through the curve. Still, if the clearance is that small, it is probably a good practice to avoid taking the chance and just run the long passenger cars through by themselves. This will be nothing more then a minor nuiscance for two reasons. One is that I am primarily a lone wolf operator so being forced to single thread the trains through the curve is not going to have that big an impact. If it were a club or I had multiple operators, it might be a bigger issue if one of them had to stop their train to allow the passenger train to clear the curve. The other reason is that the main freight yard is just beyond the curve on the inside track and any freight leaving the yard would have to wait for the passenger train to clear before moving on to the main and then crossing over to the outside track for right hand running. It would only be a problem if another passenger train was entering the curve in the opposite direction and I can easily work around that.
Luckily I tested before gluing anything. I have about a 32" radius and I thought 2" center spacing should be fine - turned out when I pinned some track in place and tested it, 80 and 85’ cars would sideswipe, so I widined the spacing on the curves out to 2 1/2". Next layout it won’t be a problem because I won’t be running anything other than 40 and 0 foot freight cars and 60’ passenger cars. 2" spacing should be fine, but I will probably use slightly smaller radius, so I will test once again. Or even more liekly it probably won’t even be HO so I will definitely have to test with N scale cars and appropriate radius curves.
The same interferance could happen when the passenger cars are on the outside track. The body overhanging the inside of the curve can hit a overhanging pilot especially on steam. I don’t think the truck to coupler overhang is as great as side mid body overhang for a 30" radius. Should double check it though.
Usually 2 1/4" is bare min, 2 1/2" gives some insurance.
I had a related experience just a couple of days ago. I have an IHC Mike that has been all over the layout, and in every direction…except for the one direction at the one diverging route entering a turnout towards the points. The problem is that the pilot is very wide and very low on this model, and the one edge caught the through route rails that are at a higher angle onto a switchback. This after ten months of track on the layout, and nearly five months of running!
Where is my Xuron…I feel the need for a nip and tuck.
I have a runaround track on a large curve at Wagon Wheel Gap on my Yuba River Sub. Outer (#2) track is 36" radius, inner #1 track, which also services the Wagon Wheel station is 34". Both tracks are Eastbound. Even with careful planning, I cannot run a train on #2 track if I’m using a prototypcally ‘articulated’ Articulated on #1. Nor, I have found out, can I run a Limited on #2 track if I’ve got a Local stopped on #1. Something about those 85’ passenger cars!
I just took my ruler out to see what I have - 2 3/16" center to center - and that’s on 19 1/2" inside 21 1/2" radius (approx., the extra 3/16 is in the center of the curve). This is all I can get on a 4x8. I run an Athern Challenger & a Lionel Turbine (about the same length) pulling 85’ passenger cars often for the grandkids - it may look rediculous, but they get real close but don’t touch! The backing manouver may well have been your problem - try pulling forward and see what happens! Good luck![:)]
I saw how close mine were at 2.25" centers and decided to go 2.50" since I had the room. I figured I didn’t know what I might buy in the future so better safe than sorry.
Just file off the corners of the cars causing the problem.[:P]
I lucked out! When I planned my RR I established a 2 1/2" track center as standard. Not for any train clearance reasons but, rather, because I figured no amount of dieting was going to make my fingers any thinner.
If it’s any consolation the real RRs have the same problem. The SP wouldn’t allow any articulateds on the line between Dunsmuir Ca and Ashland Or in spite of some really horendous grades, because they couldn’t clear the walls in curved tunnels.