Today there are about 200,000 railroad employees ~ most of them employed in freight operations. Rail right of way is probably nearly 140,000 miles, but active mileage is cited as low as 45,000 miles ~ depending on who is doing the counting, there are great differences in the mileage estimate.
The expectations are for even less employment as the roads adopt labor saving mechanization, automation, computerization and robotics. The need for miles of track will continue to drop as improved work methods and analysis will combine with intermodal technology to eliminate the need to operate less than optimal right of way.
Nice historical research but I'm not talking about 'employees'....think construction, BIG DIG, WTC Memorial.....UNION. YEARS OF IT. Trillions by the time they're done if you're talking $260 Million/mile.