While looking for something else within the bowels of my computer the other day, I came across the online edition of the Model Railroad Hobbyist (MRH for short) and found an interesting article about the minimum radius to use when designing your next layout. The article itself (by Joe Fugate) came out of several online discussions from the Layout Design SIG.
The main points that came out was that minimum radius shouldnt be a number set in stone, but should instead be a ratio, with the most important element being the actual length of the longest item of rolling stock you intend to run. The table published looked something like this:
So what does this all mean? Well, lets look at this weeks favourite prototype, Milk Trains in South Taranaki. The main stars are the OM tankers, which are about 116mm long (4½"). Looking at the table above, we can see that they will run fine on 290mm radius curves (11½", or 2½ times their length), but wont really start hitting their straps until 464mm radius curves (18½" or 4x their length). Of course, I am planning to run VRB's on the layout, which are 142mm long (5½"). Suddenly, the "Look Good" curve radius (at 4x) is 568mm, or 23".
Of course, note in the table that if I am viewing the train from the inside, I can drop down to 3.5 x the length and save some precious space.
The thing to note is that this doesnt seem to work with 4 wheelers, of which the US railroads had few (if any), but then again I dont think anyone would have a layout without some bogie wagons or carriages on it....and seeing as we are calculating with the longest item, we can arrive at a curve suitable for the layout.
And here is some visual proof, courtesy of Kiwibonds, showing Nz and US stock on the same 18" curve. Despite the difference in viewing angle, I hope you can appreciate that the shorter American stock looks better tracking around the curve than its large NZ counterparts.
4 comments:
Planning to do a layout, and have to consider 550mm to 600mm curves. Has to be able to run container trains with Uk's (or even IA's in the future). Layout will be modular for exhibitions.
So using that formula, 4 x a UK is 562mm...so that sounds about bang on.
Those will be nice big curves - keep us informed!
I'm a fan of throwing a few PKs into a container wagon mix for variety - at a glance they all pass as container wagons, but the shorter PKs look great on curves, and replacing a few UKs with them might allow you to get an extra wagon into your train length, which makes quite the visual impact. On Otaki to Cass, a train of LCs always 'looked' longer than a same length train of CBS because there were more vehicles in the consist.
I'm going to make some of those ZG/ZH fiberglass doored wagons and am going with the shorter ZH Spacerunners for that reason.
just had to comment, you say that a 4 wheel wagon would be impossibly short curves to negoiate, but what would pull such a small wagon? surlly not a 4 wheeled loco?
Graham
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