How does your light rail go?

For reasons that will become clear before long, I’ve calculated the average speed on each segment of the Hiawatha line (which apparently for the purpose of marginalizing those with color blindness has been renamed after some color, not sure which).

More precisely, I’ve calculated the average scheduled speeds – I used the posted schedule for the line and Google Earth to measure the track length to get the average speed.  Segments are measured from the apparent midpoint of each platform, and where the two tracks deviate or the tracks disappear under an airport or a megamall I guessed a bit or used the rail layer from GE.

In an interesting twist, the scheduled speeds diverge a bit from the official map.  The map shows 2 minutes between Target Field and Warehouse District stations, but 3 minutes are scheduled, perhaps for padding at this terminal, where I believe trains often reverse.  More mystifying is the reversal where the official map shows 2 minutes between Franklin and Lake and 3 between Lake and 38th, but the schedule switches those.  It makes more sense for the segment between Franklin and Lake to take a bit longer, considering the curve on the viaduct over Hiawatha, so maybe it’s a typo?  Regardless it perhaps shows the folly of relying on the scheduled time to determine average speed instead of observing in the field, but who has time to ride back and forth with a stopwatch?

Oops, forgot to mention that distance is in miles

Hiawatha runs through a fairly diverse set of environments, which I’ve broken down into three categories.  While these are probably imprecisely named, they are fairly consistent.  At-grade and Separated at-grade both have grade crossings, but Separated at-grade has far fewer.  Below grade (which I suppose I should have called grade-separated) has no grade crossings.  The At-grade segments have an overall average speed of 12 mph, while Separated at-grade doubles that to 24 mph.  Below grade is the fastest, with an overall average of 29 mph, but you may have noticed that some of the separated at-grade segments exceed this.

Clearly the segments have characteristics that differentiate them from each other more than my simplified categories suggest.  The fastest segment, between 38th and 46th, is straight and has only one grade crossing [Froggie reminded me that this segment actually has two grade crossings - see comments].  Meanwhile the segments that are largely in tunnels have quite a bit of curvature to them, and since both segments have portals grade may be an issue as well.  And of course some segments have subsegments of more than one category – between the VA and Fort Snelling are sections that are at-grade but largely free of crossings and a long above-grade section.

Central may introduce another category, since the body of it will run at-grade, but with far fewer crossings than Downtown Minneapolis or even Bloomington, yet more than Hiawatha between Franklin and the park.  So who knows if anything valuable will come from this exercise – only the fates can tell…

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6 comments on “How does your light rail go?

  1. [...] Center Transit Center to 4th & Hennepin is 13 minutes without congestion.  Based on the average speeds of Hiawatha, a light rail version of my proposed route running in a tunnel from the BNSF line to Plymouth and [...]

  2. Froggie says:

    Aren’t there 2 crossings between the 38th and 46th St stations? One at 38th, and another at 42nd.

    • Alex says:

      You are right – I think I forgot about the 38th St crossing because it’s so close to the station. Now that I think about, I don’t think the trains typically slow for grade crossings so I don’t know that it makes a difference for avg speed.

  3. mulad says:

    Hmm. This is definitely weird. I think the Hiawatha trains run a bit slower than they were initially planned to — during testing, some neighbors complained about horns, so I’d heard that the horn volumes were reduced slightly and the speeds along Hiawatha Ave were reduced somewhat (since you can’t hear a quieter horn from as far away). I think the segment between Franklin and Lake is one of the few spots where the 55 mph top speed is reached. A smartphone with GPS is sufficient to test this, and there are a few speed limit signs along the route here and there. I suspect the airport tunnels may also support 55 mph for most of their length, but being underground makes GPS testing impossible, unfortunately.

    So, if anything, I would have expected schedules to show a longer travel time between Lake and 38th than the map does, but whatever.

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