Presumably, planning that took place 100 years ago when a train would pass by in 60 seconds or so. Once you've built the rails, built the roads, sold off the l

Presumably, planning that took place 100 years ago when a train would pass by in 60 seconds or so. Once you've built the rails, built the roads, sold off the land nearby and constructed buildings, adding a bridge later can be difficult. If your bridge is 22 feet high, and the approach ramps have a 6% slope, each approach ramp will be 360 feet long.