The layout I’m building will have 24 inch minimum radius curves. I want to run some passenger trains and I would like them to be as accurate as feasible. Will 85’ passenger cars negotiate a 24 inch radius, or do I need to compromise and go with shorter models for smoother operation? Thanks!
Are the couplers on the passenger cars body-mounted or truck-mounted? You can handle much tighter curves with truck-mounted couplers.
depends. Some will, some won’t. consult their boxes (if you’re buying them from a LHS), and see what they say. Although, even if they will work on a 24" radius, you might want to go shorter anyway, just for looks.
I have seen my weighted 85’ HW cars run OK (not great) on 22" curves but they look pretty hideous. I converted them to body-mounted couplers and metal wheel sets and will eventually run them only on broad curves (not sure yet about the radius, but probably will be minimum 28"-32"). If your 24" minimum plan is in stone, I would go for shorter cars.
<>My last HO layout’s mainline minimum radius was 28", but I did have a 22"R section that I could use to test out passenger cars etc. I found that if they have truck mounted couplers, 80’ cars will go down to at least 22" radius quite well. They might not look that good but they will do it. Cars with body mounted couplers won’t, even the Walthers 60’ cars have trouble with 22" R.
If your curves are hidden - like if you have a long ‘dogbone’ layout let’s say - you can use long cars with truck mounted couplers, since the cars won’t be seen going thru the tight 24"R curves. If the curves are out in the open, you might want to use shorter cars for appearance’s sake (but still stick with truck mounted couplers).
BTW keep in mind in the heavyweight / steam era, many RPO and Baggage cars were 60’-70’, and many Combines and Coaches were around 70’-72’ long. So you could run a train of say Athearn’s RPO - Baggage - Coach - Coach where all the cars are ‘fullsize’ despite they’re all being between 63’ and 72’.
The Rivarossi/AHM/IHC type passenger cars will run on sharp curves such as 22" and maybe even down to 18"
That is only partly because of the truck mounted couplers. It is also partliy because they have modified the steps and underbody from scale accuracy to clear the coupler. I have not tested the new generation of really nice accurate cars but if all you have is truck mounted couplers but accurate to scale steps, air and steam hoses, and other details, I doubt if you can get down to 22" without modifications.
I can tell you that there is quite a bit of overhang even with 40" and 42" radius curves.
Another issue to think about is clearances. I built a test track before I chose the minimum radius for my layout. I knew I wanted 2" track centers and I also knew that if at all possible I wanted to retain that spacing for curves. (Sharp curves need to have wider track centers for the curves than for the tangents). My experimenting showed that I could keep my 2" centers down to 38" and 40" radius double track curves. But once I tried to get it down to 36" and 38" double track radius curves I could see a possibility of side swipes for certain cars. Getting it down to 34" and 36" made it virtually a certainty that there would be side swipes. And in practical reality when you are laying flex track there is a bit of variance in the curves.
True story: a friend who is a professional superdetailer and custom painter but who has no layout once took an entire passenger train – I think maybe the 1938 Hiawatha --that he had laboriously painted and detailed to operate on a friend’s large layout. Not only did the train derail more than once because he had done nothing to prepare for the kind of radius and clearances a true operating model needs, but many of his expensive detail parts ended up scattered all ove
“His conclusion: a perfect model and an operating model might be two different things.”
One of the all time best lines I have ever read on here. I have a “short passenger car phobia”, so I do not make curves on my layout less than 30". And I test them on 28". I am willing to trade semi bad looks on curves for pretty good looks on straights. You need to decide which is more important to you.
I have every type of amtrak car walthers makes (superliner, budd, horizon, etc) and they all run just fine on my 22" curve, which BTW is a full half circle not a quarter circle. I have made no modification to them and thy have never derailed on me, yeah they would look better on larger curves but mine is in a tunnel so i never see them. If your track work is good you will have very little problems, if your track or benchwork for that matter is not so good then you will have nothing but issues.
Thanks for the replies everyone, some good information for me to consider. I feel a little better about opting for shorter cars now. Having them look good as they run is worth considering in addition to strict tolerances.
This is why I went N scale 
Unless you’re modeling narrow gauge or a trolley operation, any radius curve under 36" in HO should be BANNED!
My mins on the main are 28", with most curves in excess of 36". Even then, the hw cars look somewhat out of place. As I have stated in other threads, the difference in looks between a string of long passenger cars on 22" curves compared to 28" curves is not appreciable for all but the most discerning. The majority of us won’t see any meaningful difference. In fact, it is not until you get up into the 40-plus" range that you begin to say, “Aha! This is what they were meant to look like!”
I made very sure that I didn’t dip down below 24" in my yard throat, yard, and in my one reversing “S” because I wanted to be able to run the hw cars down there at times to snake through the lone double-slip switch, which I am pleased to say they do at yard speed. Mostly, though, the monster 2-10-4 had to be able to get through all those places, my drop-dead bottom line given.
If your tracklaying is solid, you can probably walk your hw cars, and similar lengths, through 22" curves, but that is all. You’ll need good 24" curves to run over 30 scale mph.
[swg] I love passenger trains. Long platforms with people, watching the steps ease over the concrete as passengers anxiously await their ride. I love diagphrams inbetween coaches on straight track. Chuck Hitchcock on his Argentine Division was a stickler for scale separation of his passenger cars with Walthers bellows diagphrams. I’ve been building these cars since 1959, and continue to build them today.
Athearn cars should work, with their couplers attached to the trucks, and they can be detailed up to look good. They will hang over a little bit, but should work. Walther’s 60 footers, Model Power, Bachman Spectrum, OK Streamliners; all should work because of their coupler attachment.
The problem begins when you lengthen the cars, body mounted couplers and diagphrams. I love diagphrams. It the best thing about modeling passenger trains. When you add that detail is when you can get into trouble. Walther’s and Rivorossi streamlined and heavy weights look great, but they have a problem with a 28 radius, no matter what folks say. I don’t know about the Canadian Company Rapido’s new passenger cars, which look spectacular. Over all, the 85 footers just look better on larger radii. I keep mine at 38 to 42 inches and the cars look good and run well. As long as the end of the table for your curves is 6 feet you should be alright.
O.K., with all of this said, banking your curves will truly make a difference. I start with the curves flat on the road bed, then start running cars around the curve and watch the trucks. If I see any lifting, wheels riding over the track (jumping), I start placing styrene shims on the out side of the curve and raising the track gradually. It won’t take much, but you will reach a height on the bank that the cars run a lot smoother.
Passenger trains are wonderful, love getting eye level and watching them go by, hope this will help.
Yard Master
WTRR
Here is a photo of my passenger train on our club layout. Our minimum radius for mainline is 42" and this particular curve is about 44". Look at the gap between the last 2 cars. It is never going to look perfect.
Even with large radius curves, there is still some overhang with long passenger cars or locomotives. It is more noticeable on the inside of the curve.
Most 85’ passenger cars can be made to run quite well on 24" radius curves. Even with body mounted couplers. In some cases you have to use longer shank couplers or mount the couplers so the car bodies don’t touch on tight turns.
You might have to modify the center sill or trucks so they don’t interfere. Operating diaphragms are another problem…
Bottom line… Use as large a radius as you have space for, but don’t be afraid to run 85’ cars with body mounted couplers …
I have one of the Walthers 60’ RPOs. Runs fine on 18" radius. I did put Kadee 5s on it.
Real passenger cars have a long shank coupler. The pivot point is 3-4 feet back from the end of the car. The air and steam lines rode on a carrier that slid along with the coupler. The Walthers draft gear arrangement replicates this functionality. The air and steam lines would be kinda hard to put in. I recall an article in MR about making replacement trip pins for the couplers that had steam line detailing on it.
I am planning to run passenger cars on N-scale. I have Kato Superliners which have trunk-mounted couplers and Kato California Zephyr which are body-mounted. My layout is 11’ x 12’ and I am planning to have a radius between 16-18" (my druthers)
Would this be fine? I need to balance between appearance and operations. Visit my blog - http://mytrainmaster.space.live.com
Thks
Jimmy Low
Kuala Lumpur, Malaysia