These are great, but they aren't walkable so I am unable to build them across a large sea space. Any way to make it so I can walk along it while building? I have tried looking through the mod files to see if I could find what blocks the player from being able to move on it, but can't see anything that pops out.

I second this. I can build straight across large spans of water by using the rail planner (as it will continue placing a single block of rail every time I click, even once out of sight), but it would really be nice to be able to walk across the bridges. As it is, it takes forever to build long four-lane bridges, and then I have to get in my train and ride across it while manually placing signals and power poles as I slowly drive and stop, drive and stop.

@thegroundbelowme, I actually never thought to try building while inside a train. Is that possible? Can I just sit in the train and build the bridge?

@eecer You can always build around even in a vehicle so yes you can (also with a roboport in your armor it remove boulders and trees in the way while placing the rails :D)

BTW i am for this sugestion, either that or an instant death if you get off the train.