I'm working on a project that involves mapping parts of the Freight Main Line, and there have been a couple of interesting things I've noticed about the mileposts. The first is that when GTI renumbered all of the mileposts to start in Mattawamkeag they didn't actually remeasure anything - all they did was renumber the existing mileposts that dated back to the 1920's (or earlier) that were based on the MEC's measurements from Portland and the B&M's measurements from Boston. The second thing is that in places where mileposts based on measurements via one route meet up with mileposts measured via a different route the distance from one milepost to the next is significantly more than the normal variation you normally see (where a "mile" can be anywhere from 4800 feet to
5500 feet) that happens because of line changes and other typical things over time. While I've often come across "short miles" that are created in these situations to make numbers match up, there's an unusual "long mile" that has me curious. Just west of Waterville, the distance between MP 113 and MP 114 is about 1.5 miles. East of Waterville the mileposts are measured from Portland via Augusta (the Low Road), while west of there the mileposts are measured from Portland via the Back Road.
Here's my question: How do engineering/maintenance crews or operating crews identify locations within that area and determine where things are? Looking at the milepost numbers assigned to crossings and bridges in that section doesn't help - based on the data in the FRA's crossing database, the Chaplin St (MP 113.78) and Main St (MP 113.88) crossings should be west of the North St bridge over the tracks (MP 113.65), when in fact, they're 1/4 mile EAST of it. Is there a section of "repeat" mileposts to allow for the extra 1/2 mile between 113 and 114? If so, are they identified in any way to avoid confusion with each other, or is this simply one of those things employees are expected to know that falls under the heading of "knowing the railroad"?
Thanks for indulging my curiosity.
Joshua Moldover
5500 feet) that happens because of line changes and other typical things over time. While I've often come across "short miles" that are created in these situations to make numbers match up, there's an unusual "long mile" that has me curious. Just west of Waterville, the distance between MP 113 and MP 114 is about 1.5 miles. East of Waterville the mileposts are measured from Portland via Augusta (the Low Road), while west of there the mileposts are measured from Portland via the Back Road.
Here's my question: How do engineering/maintenance crews or operating crews identify locations within that area and determine where things are? Looking at the milepost numbers assigned to crossings and bridges in that section doesn't help - based on the data in the FRA's crossing database, the Chaplin St (MP 113.78) and Main St (MP 113.88) crossings should be west of the North St bridge over the tracks (MP 113.65), when in fact, they're 1/4 mile EAST of it. Is there a section of "repeat" mileposts to allow for the extra 1/2 mile between 113 and 114? If so, are they identified in any way to avoid confusion with each other, or is this simply one of those things employees are expected to know that falls under the heading of "knowing the railroad"?
Thanks for indulging my curiosity.
Joshua Moldover