allowable grades

I am trying to plan my new layout and the best I can accomplish is 4%. My layout will have a five or six car train and a rail bus with 2 cars. I need some input.

Thanks, Tom

What do you mean by best you can accomplish? I hope you aren't implying that this is the minimum grade you plan to have

Generally, recommendations usually are to stay below 2% but given your limitation of short trains, up to 4% ought to work out OK. My home layout will also include a 4% grade over a 1/3 scale mile.

Thomas, 4% is doable. I just did a quick test for you and my two GP-9 pulled 7 cars up an approximate 7 or 8% grade. No curves just strait track with no problems. Good luck, Jim CCRR:)

Hi Tom

Welcome to the forum! My layout has two 3.5% grades, one on a straight stretch and the other on a curve. An E44 can easily pull five 120 mm coaches up the former, but it struggles a bit on the curved grade. I also have a VT11.5 seven car set and it has no problems whatsoever on both grades. And neither does my Br 53 with up to 15 2-axle wagons in tow

Gary points out an important point about grades and curves, essentially that each presents resistance to the moving train and having both at the same time makes these resistances additive.

I did a little research and found out that it is generally accepted in prototype trains that the curve resistance is roughly equivalent to 0.04% of a 1% grade per degree of curvature. So, let say we are talking about a radius of 8.67 inches (220mm track, ~39 degrees of curvature using US 100 foot stations) ... the resulting increase in resistance in the curve would be roughly equivalent to having a 1.56% straight grade. For the smaller standard curve 7.68 inches (195mm track, ~45 degrees of curvature), the rough equivalent would be 1.8% straight grade. This all assumes that I got my math right, including scaling down from prototype standards, but at first blush the numbers seem reasonable.

Obviously if you can open up those curves to say a 12 inch radius, then the curvature impact can be less, approximating a 1.1% straight grade.

I now realize that the 4% grade that I have on my layout is much more like a 5.5% grade in the curved section of the mainline!

Here's a video showing an AZL GP7 at work on >4% grades and <6" curves. It has no problems at all and can easily haul a train twice as long.