I know railcraft stairs all use the same block id and use NBT data for the type of stairs and the rotation, but it also makes them incompatible with pistons because they become tile entities. On top of that builders / block placers always place sandy bricks stairs regardless of the type of stairs.

If nothing else this is a bug report on an exploit that lets you turn any railcraft stair like cheap snow stairs into sandy brick for an easy creosote oven. However it's also a request to make railcraft stairs compatible with at least the builder since its from a mod that goes hand and hand with railcraft. Even if it's just a new config option that makes railcraft stairs act like vanilla stairs at the cost of 30 or more ids it would be a relatively easy fix for people who don't use a whole lot of mods anyways.

If SpaceToad had listened to me about the Builder API, this wouldn't be an issue. As it stands its his issue now, not mine.

The builder SHOULD NOT be placing Tile Entity blocks by default.