Investigate why speed from line speeds page doesn't match speed from

[rudiejd]

On the speed page for the Mattapan trolley, the displayed speed across the line doesn't match the speed for multi-day trips from Ashmont to Mattapan or from Mattapan to Ashmont. The displayed line speed for the Mattapan line is 23MPH whereas the speed from terminal to terminal is 18-19MPH. We should figure out why this is happening

[devinmatte]

First step is to ensure we're using the same distance numbers in both sets of code, for all lines.

Using the distances from https://gis.data.mass.gov/datasets/MassDOT::mbta-rapid-transit-stop-distances/about seems like the best way to ensure consistency.

Also need to confirm if this is happening with other lines or only with Mattapan. If only with Mattapan we may need to hide speed until Mattapan eastbound data is available