My guess is that the failure is related to signalling or some other knowledge that exists “between” the trains (and brains). Having systems that can negotiate right of way is necessary to increase the number of trains and the speed of each individual train beyond their pre-computer-era limits.
Having all trains stop for one day is probably a judgment call to lower the overall duration: Having all trains stop for a day is a pain in the neck, but you know when you’re done. If you could not wait, you could probably have (quite) a few trains run without problems. However, you would have to work for a very long time to get all the trains back to where they were to resume the regular time table. This would be the preferable option during a time of crisis.