train size

[Anonymous]

I have about 9 1/2'' radius 90 degree turns in my layout. My layout is N scale. How long of trains could I run?
How many cars?
How many engines?

Thanx for the help

Benjamin R.

[Jetrock]

Your curves do not limit the length of your trains, number of cars or number of engines. They do limit the rolling stock you can operate--longer engines and longer cars (70-80') might not do so well on those curves.

The length of your trains and number of cars (obviously closely related) depends on the number and power of the locomotives pulling it, as well as the total length of your mainline--one could theoretically run a train all the way around a loop, with the engine following close behind its own caboose!

The number of engines you can run (I assume all working together) depends on the capacity of your power pack and the current draw of the engines.

[DSchmitt]

I rarely disagree with Jetrock, but he is mistaken about curve radius not affecting the length of train. Awhile back there was a thread regarding "compensating grades". Prototype railroads often reduce the steepnes of a grade on curves to compensate for the resistance caused by the curve. In the book Railway Track and Maintenance the figure of 0.04 percent grade = 1 degree of curvature is mentioned as a commonly used value. (This figure is for the prototype and whlie the same principles apply the numbers may not be applicable to model railroads) The prototype measures curves in degrees, not radius. A 40 degree curve is 10-3/4 inch radius in N Scale. A 50 degree curve 8-5/8 inches.

The prototype uses easments, superelevation, and slightly widened gauge on curves to lower the resistance.

Adding more power to the front of the train would only work up to a point. If the train were long enough, the resistance would cause cars to be pulled off the track to the inside of the curve. If the locos are distributed throughout the train a longer train would be possible assuming the locos worked well together.

The types of trucks, wheels, couplers, and the weights of your cars will also make a difference.
.
From a practical standpoint, however, Jetrock is correct. The main adverse affect of sharp curves on a model railroad is to restrict the size of equipment that can be operated, since model trains are generally very short anyway.

[Anonymous]

Thanx for the help