SCRTD Electronic Headsign

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In the Southern California Rapid Transit District and going back to most buses in the old Los Angeles Metropolitan Transit Authority (MTA), headsigns were "split curtain" meanding there were two signs that faced the front.  One sign (often referred to as the "shortsign") contained the line numbers while the larger sign contained the destinations.  Because of the size of the system, headsigns were divided by divisions and many times, two divisions were combined into a single sign (such as 8 & 15, 6 & 7, 5 & 12, etc.).  

Inside the standee window closest to the front of the bus on the curb side (and for the new look GMC buses, cleverly placed in the teardrop-shaped quarter window) was a 3 scroll rollsign used to indicate the line number.  Each scroll would contain the digits 0 through 9 and the letter X.  The same scrolls were used for the 2 scroll bus run number mounted on the dash facing forward, and the "X" usually indicated an "extra" bus added to the line.    The third scroll on the side-sign also included the letters (if memory serves me right): A, B, D, E, F, G, H, K, L, M, P, S, T, V and W as those were used to construct line numbers with letters in them (e.g. 39G, 56P, 91W, etc.).  

In the early 1980s as the RTD was starting to take delivery of their first Flexible Metro 870 buses, these buses were delivered with the first electronic headsigns.  These were very archaic (in today's standards) signs with a 15 5x7 flip-dot matrix characters.  These signs were manufactured by Luminator.  With the delivery of the first RTS-04 coaches, RTD went with the Transign TransDot electronic destination signs.  Like with the Luminator signs, destinations were selected using thumbwheel switches.  A unique feature about RTD's Luminator and Transign signs was that in addition to the thumbwheels used to select the destination, there were also three thumbwheels used to select a route number.  This was not common in signs delivered to other transit agencies.   

The Luminator signs used a decimal format (0,1,2,3,4,5,6,7,8,9) for their destination codes where the Transign signs used a hexidecimal format (0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,F) for their destination codes.  As a result, headsign instructions given to operators for each route included codes for both headsign types.  In the Transign signs, the data for the headsigns were stored on erasable programmable read only memory (EPROM) chips (type 2708).  Each chip can hold up to 128 lines of information. 

In addition to all of the new full size coaches being delivered with dot signs, RTD retrofitted their newer "new look" buses and their AMG buses acquired in the late 70s with the Transign signs.  The retrofits had a full headsign to the front and had a 3-character side sign.  These sidesigns were mounted in the most forward standee window (even on the GM new looks).  For the buses that would eventually be disposed of after the Olympics in 1984, the division specific headsigns and shortsigns were removed and replaced with a common headsign type with about 150 exposures that covered the entire system at the time.  Many street specific exposures were replaced by community names.  For example, on the 243 (formerly 153), "Winnetka-Ventura" was replaced with "Woodland Hills".  The short sign was removed completely and replaced with a short piece of blank yellow mylar.   The route number was given through the use of dash signs and the three digit side sign.

These are the readings from an Transign TransDot generation 1 destination sign pulled from a former SCRTD GMC TDH-5307.  This unit included 12 EPROMs.  

In these readings, the characters in blue were what was also displayed in the side sign.  The # characters indicate the route number that was entered on the additional 3 thumbwheel switches.

We will go through the headsign readings, two EPROMs at a time...