Rail Repair

[LordDeadwood]

Just wondering if a mechanism for rail repair, esp. for long campaign scenarios, had ever been considered? I don't know how long it typically would take to repair rail lines damaged/sabotaged by the opposing army would take, but it seems to me that some of the long scenarios (i.e., France 40 or Normandy 44 Grand Campaign) cover enough time to give rail repair a realistic chance at success. Any idea of how much time was needed? Days, weeks, months? My efforts at Googling such information came up empty. Just curious...