Milepost/Distance question in the Waterville area

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

The crossings are typically referred to by name not mileage by employees. However when using a Form D the mileage is also used.

So since the mileage numbers are given for specific points, and not for actual distances, the fact that they go up, then down, then back up (in order) doesn't really matter? I guess part of what I'm wondering is how the mileage number would be determined if a new bridge or crossing was built in that section. Where would it be measured from?

Thanks.

That I don't know. From an operational perspective, as long as what someone is referring to matches what's in the timetable its good though.

The 113 is a control point and the whole area from roughly 112 to 114 is all from when the roadways in downtown Waterville were rerouted into the current form, which required the realignment of the track pattern. Which is likely for the "long" mile. It could also be due to the placement of the ABS signals, or the actual milepost falling in the middle of the crossing, or any other plausible reason of that nature.

I'm pretty sure (having looked at the valuation maps from 1916 and seen that both the main line tracks and the two roads I mentioned (Main St & Chaplin St) are in the exact same place today as they were 100 years ago) that the tracks in that area haven't been moved that much... The fact that the mileposts as measured on the track chart and shown on the valuation maps are also in the exact same location as their predecessors (MP 113, formerly MP 82 via the Low Road, at VS 1+73, and MP 114, formerly MP 84 via the Back Road, at VS 3737+59.6) also tends to make me think that the long mile is more a result of GTI having renumbered everything, and not taking into account the fact that the next milepost via the current main line (114) wasn't being measured from the same place as the previous one was (113).