Signal 2711and 2712

While the eastward fleet shows no sign of abating, the westward fleet now begins to materialize. Night is a time of heighten activity on the 2nd District, and great excitement to all who watch, dispatch and run. There are few speed restrictions on the 2nd district. This is an ATS railroad carded 90 mph for passengers and 70 mph for freight. The 2nd District was once compared to a raceway, where many overall speed records were set. As a result, most signals on the line have a flashing yellow for an advance approach indication, giving the engineer an added block to slow his train for a more restrictive block ahead. But the great advantage of the flashing yellow is that it allows closer spacing of trains with greater safety. In double track, high density territory it is easy for an engineer to get in the dangerous habit of "riding the yellow", where, knowing that a train ahead is running roughly at the same speed, he cavalierly assumes the next signal to be yellow. This could go on for block after block and be OK until finally one day the train ahead stopped for unknown reasons, with the rearend just ahead of the red signal. On the other hand, to hold back for nothing but green signals means the train could be way more than 3 blocks ahead, giving more separation than necessary and also causing the engineer to constantly modulate the speed should he catch the train ahead. Green: up to 60mph; yellow, back to 40mph, prepare to stop next signal; green, back up to 60mph; yellow, back to 40mph; etc. With the flashing yellow, the engineer can keep a closer spacing, keep a more steady speed, and still be in safe stopping distance of the train ahead.