Re: 3 3/4 scale - track gauge?

The answer as to sub structure really depends on the scale, weight of equipment, and local soil conditions. When Train Mountain was started some 30 years ago these were NOT part of the design criteria. We just built 7.5 in track panels with 16 in ties, aluminum rail on cedar wood ties, 75 ft min radius, and #9 switches (75 ft). . Most visiting trains were an engine, an engineer car, maybe one or two rail cars and even a possible caboose.

Now we run trains around 120 to 140 feet long. Seeing the trends these days we should have had at least 24 in ties. The main reason is our soil base is not actually dirt but volcanic pumice and so it never really packs down. Running the heavier equipment and longer trains is causing some issues with the ties sinking into the sub grade and making for a rough ride. We also had been using 3/4 crushed washed stone for the ballast and it also would not pack in tightly around the ties. We are now using 1/4 by 1/2 crushed washed stone and it seems to be helping some.

Were we to start over our tie spacing would be slightly wider apart (more space for ballast), 24 in ties, plastic ties, steel rail, 100 ft min radius curves, #11 switches (100 ft), and the smaller ballast stone. One of our K's weighs some 2800 lbs. Russ