A job is happening now on I-80 that will do something similar: lower the freeway to increase clearances at older overcrossings. Makes for a traveling traffic mess (not doing all of them at once) but it's cheaper than building new bridges (especially as an emergency project after a wayward truck takes one out). Parts of 80 were built before modern Interstate standards were set, and resurfacing jobs over time cut the clearance a bit more. Not sure if any RR bridges are involved.

Here are the Federal clearance standards if anybody's interested.

Clearances for going over railroad tracks (that's an "overhead" in road terminology) have evolved over the years, too. Not sure what the minimums are now, but in the 1980s I vaguely recall a couple of jobs where they would have normally been designed for something between 20-25 feet, but SP wanted over 30 feet to allow for future electrification (ha!). IIRC SP didn't get what they wanted, but that wasn't why the wires never went up. What's current standard for double-stacks?