Whats the steepest gradient I can expect a typical park engine to pull a loaded train up?
The guage of the track has no effect on railroad engineering. Grades should be kept to a minimum as much as possible. If Union Pacific or Norfolk Southern consider a grade very steep, your Backyard & City Park Railway should too. Grades of 5% are about the top practical limit I’ve heard of being negotiated successfully (on the Portland Zoo’s 30″ guage railroad in Oregon), with 2% being much more realistic. Older, straight-boilered Cagneys are notoriously underpowered for anything but level track. Most of the newer locomotives will pull a decent hill (say 2-3 %), provided the trains aren’t too long. Chance Rides has some gradient statistics for their C.P.Huntington on their website. Don’t forget to include an easement (a.k.a. transition) in your grade layout. Suddenly going from flat track to a 3″ grade is going to cause problems like pilots digging in, or derailments because one end of the train is hanging in midair as the thing tips over the top! Include about three carlegnths (using
