Whats the sharpest curve I can use?
This is largely dependant on track guage. You can put a 12″ guage MTC G-12 around a much sharper curve than a 36″ guage Crown 4-4-0 will negotiate. One thing to keep in mind is that very sharp curves contribute to both rail and wheel flange wear. Also, curves do contribute to the rolling resistance of a train. Placing a sharp curve on a steep grade virtually increases the grade because of the added rolling resistance. A good rule of thumb is to lay out the widest curve you think will work, then double the radius. Remember that curves are always twice as sharp as you think they are!
