The Designation Sign Design
of the MFL

This was originally posted on cohost.

On the Market–Frankford trains of SEPTA in Philadelphia, the designation signs indicating the line and the next stop are very simple 18-panel 3×5-segment displays.


But they aren’t merely square segments! Each square may be subdivided into subsegments of triangles or quarter circles to give the the letters some ✨character✨, and so that some letters can actually fit within the grid. Taking a closer look at the segments, we can see the subsegment outlines.


(The N and the K are two of my favourite letters in this set — I just think the design is clever.) Combining the outlines of a sample of letters, a single panel is subdivided as follows.

a three-by-five square grid further subdivided into subsegments. the four corners have quarter-circle segments. the middle three horizontally and vertically have an X dividing the square into four triangles. the bottom two left and right squares have mirroring diagonals through them inwards towards the middle going down.

This suffices to display all of the letters, digits, and punctuation needed by the MFL, which are all letters excluding J, Q, V, W, Z; all digits excluding 71; and the punctuation :, -, '. The letters are used mostly2 in the northeast Philly stations, which are, in order towards the northwesternmost terminus:

  • Spring Garden
  • Girard
  • Berks
  • York-Dauphin
  • Huntingdon
  • Somerset
  • Allegheny
  • Tioga
  • Erie-Torresdale
  • Church
  • Arrott Transportation Center
  • Frankford Transportation Center

You’ll notice a number of these are quite a bit longer than 18 characters in length. I was curious to see how they abbreviated those station names, so I took the train all the way to the terminus and took photos of each displayed sign.

York-Dauphin fits beautifully and fills all 18 panels; poor Erie-Torresdale has a third of its name abbreviated away; Spring Garden very nearly fits but does away with one letter (as does ALL STOPS - FRANKFRD).

From these signs, I’ve recreated all of the letters, digits, and punctuation used3, and also speculated on what J, Q, V, W, Z, 7 might look like. I’ve taken the J, V, W, Z from the San Francisco Muni Metro’s LRV4 designation signs, while I haven’t found a sample for Q or 7.

a grid of all 26 letters and 10 digits, a dash, a colon, and an apostrophe. they're in the style of the designation signs.

Personally, though, I would have made some of the digits a little more distinctive…

0 1 4
  • 0 contains a marking in the middle to distinguish from O
  • 1 has a hook and a foot to distinguish from I
  • 4 has a cut corner in the middle left to match the other digits
  1. The stations of numbered streets are 69, 63, 60, 56, 52, 46, 40, 34, 30, 15, 13, 11, 8, 5, 2, and so feature all digits except 7. Because of how the existing stations are spaced, and because 27th doesn’t cross Market at all, it’s unlikely they’ll ever add a station with a 7. 

  2. There’s one more station with a nonnumbered name: Millbourne, which is the second westernmost station, all the way at the other end. 

  3. I omitted because it’s identical to 1; yes, I know O is also identical to 0,