Franklin Roosevelt actually said...

I cannot wait until the last moment to take action to see that the supplies to our fighting men are not interrupted.

I am accordingly obliged to take over at once temporary possession and control of the railroads to insure their continued operation.

The major military offensives now planned must not be delayed by the interruption of vital transportation facilities.

If any employees of the railroads now strike, they will be striking against the Government of the United States.