Wide gauge issue from marker 423 to 411, requires tie work
Could you elaborate? My "educated outsider" understanding this that
- gauge/gage is the distance between the rails, measured at the inside of the railhead.
- That
MBTA's gage limits for standard gage of 56.5"/1435mm (PDF page 17 et seq) allows for -1/4" of narrowing and +1/2" of widening on straight track, shifted 1/8" to 1/4" wider on curves (so that flanges don't squeal or, worse, ride up)
- That the main job of ties is to keep the rails from spreading (dropping the wheels into the roadbed), with it being bad to be too narrow, but not usually the problem, since the weight of the train naturally pushes out on the rails, not in.
- The main problem as ties age is that they get soft allowing the spikes to work outward or lift up, which allows the rails to be slid or tipped outward.
So that "wide gauge requires tie work" might be said by a layperson as "ties have gotten weak, allowing the rails to be between 3/4" and 1" too far apart, with the danger that a fast train might exert enough pressure to tip/thrust the railhead out, slip out from under the wheel flange, and drop the train onto the roadbed."
Reading onward in the document above (which is a really cool document, by the way), the first bit of spreading gets you a 25mph limit "Yellow", and further puts the track in "Red", a 10mph limit, with the aim of limiting the train's ability to nudge sideways on the rail.
The rules also say that repairs must be "scheduled within 72 hours" for a Yellow and "repair within 24 hours" for a red. Is "scheduled within..." different from "repaired within.." (seems like Yellow gets put on a "the list" but not fixed). And does the T keep to these standards of responsiveness?