General Tips - Gradients
You can do a lot in N gauge with narrow or single baseboards, especially if you are willing to use a multi-level design. This, of course, requires gradients, often the steeper the better. That begs the question of how steep can they be for various train lengths.
- The basic way of determining the maximum gradient for a layout is to experiment. Put two or three yards of track on a solid piece of timber, then prop it up at various angles and try to run trains of different lengths up it. If you don't have a controller handy, you can use a 9V battery and just press the terminals against the rails.
- Simple experiments give you values for straight track. For curves, you need to ease the gradient significantly. For 12" curves, I reduce the slope by a third: 1in 50 becomes 1 in 75 or 80. If you prefer percentages, 2% becomes 1.3%.
- If you have a double track curve on a gradient, try to make the outer track the one that climbs. This track will be longer than the inner one and also have a gentler curve, so less rolling resistance.
- Err on the side of caution: locos and rolling stock do vary and you may find that new loco or train cannot make it up the hill.
- Maintenance can also be an issue: if a locomotive's weight distribution is changed its hauling power can be greatly reduced. For steam locos, check the loco-tender drawbar and ensure that there is adequate free movement both up and down. For some old Farish locos, I find that I have to loosen the drawbar retaining screw slightly.
- Modern diesel locos can generally handle heavier loads and steeper gradients than steamers due to all-wheel drive and good weight distribution.
- Try to use gentle transition gradients at the top and bottom of hills. The simplest way is to let the timber of the trackbed bend into the new gradient naturally.
- Be wary of steep gradients on hidden track or storage roads: if you have to assemble or uncouple a train then vehicles will tend to roll away from you.
- If you are desperate, you can sometimes gain a bit of extra clearance below a station by elevating the end of a siding. To avoid having vehicles roll away, you can put a small magnet under the buffer stop if you use magnetic couplings (Kaydee, Microtrains, B&B, DG, etc). This will hold vehicles in place and yet still allow them to be pulled away by a locomotive.
- You can often relax the gradient restrictions for minor elevation changes or over short distances. What really matters is the elevation change over the full length of a maximum-length train. You can use a steeper gradient followed by a flat section to cross another track. This may look strange, and so works best with partly hidden track. For example, I have a 1 in 50 gradient with 7 coach trains. That works out to a train length of 45-50 inches, for a total elevation change of 1 inch. A rise of half an inch (at any gradient) would be equivalent to 1 in 100 and hence not much of a problem.