Bill, Since the prototype Western Maryland Railway Black Fork Grade is over 3.5%, 4% seemed the logical choice. Way back 5 years ago, I tested my engines pulling cars up various grades I mocked up on the floor. As I recall all the engines could pull trains of the lengths I would use on this small layout up even steeper grades. Perhaps those who are saying that is too steep are pulling trains of 10, 20, 30 cars up long grades on much longer layouts. Then I could see they could get in trouble.
The transitions were really trial and error. On past layouts, I used the old cookie cutter method of cutting the plywood and putting in risers to make any grade I wanted with automatic easy transitions from horizontal to the grade. On this layout, since the SCARM grades were near 4% and my carpentry skills are digressing, I copped out and used Woodland Scenics 4% foam risers. The problem with them is, you have to taper into the grade at the bottom of the grade and then back out to horizontal at the top. I had one steam engine that kept shorting out at the bottom of the grade, and front wheels would lift off the track at the top of the grade. I did so much cutting and shimming, it would have been easier to go back to the cookie cutter I learned back in the old Kalmbach Publishing book, 'HO Railroad that Grows' that I just about wore out when I was a teenager in the late '60s and early '70s. If I build another layout, I'll go back to the plywood cookie cutter method for sure!
