This page covers a specific style of color light signals signals nicknamed "tri-lights",
so named because of the triangular placement of the lenses. Please read my
disclaimer at the bottom of the page for an editorial on the use of the term
Like other "types" of signals such as semaphores, searchlights, Pennsy Position Lights (PL's), and B&O Color Position Lights (CPL's), this signal style is being phased out in favor of the standard
Color Light Signal. Berea, a suburb of Cleveland OH, is one of many locations
where this has recently happened.
GRS (now Alstom), US&S, and Safetran all make this style of signal.
The picture at the top of the page is from Havre de Grace MD, on Amtrak's Northeast Corridor, SB as you come off the Susquehanna River bridge,
notice the signal uses LED's! More on that page.
As you can see, "tri-light" signals can display a maximum of three colors, usually red, yellow, and green, with
green on the upper right side, and red at the bottom. I guess in theory they could have any color lens in them, or reverse the green and yellow positions. If anyone has pictures of anything other than
a typical R/Y/G arrangement, maybe you could email a picture or two to me?
When using only one or two aspects, the railroads had two different ways of handling the situation. One, they could just use the same 3-position head and blank out the unused position. Or, they could use
a two or single aspect housing. An example of all three of the latter on one signal installation is from Berea OH (left below). When using a full head and they blank out the unused positions, they usually
keep the positions filled with the normal lens color.
This was the first location I had seen using LED lamps, probably around 2002 or so (Pierce Junction in Houston was the second location in
2006). I got my first glimpse of them while riding a MARC commuter train up to Perryville and back. It is located on Amtrak's North
East Corridor, just south of the Susquehanna River bridge and Perryville MD, and controls interlocking for the 4-to-2 squeeze to go over the bridge.
SB signals where it goes from 2 tracks to 4.
NB signals where it goes from 4 to 2 tracks for the trip over the Susquehanna.
An approach signal in Harrisburg PA on the western shore of the Susquehanna, this illustrates the practice
of blanking out unused lamp positions as mentioned way up above. The signal was installed during the Penn Central days.
MP 200 on the NS (ex Pennsy) Mainline between Harrisburg and Pittsburgh. These signals were put in during the Conrail days, as were most of the tri-light
installations on the Middle Division. Very easy access from US22.
Just north of the station, on the other (north) side of Taylor St, is an interlocking, where the double tracks that go thru San Diego go into one for their trip
northward towards Los Angles. It looks like yellow is on the right side here, as opposed to the left side on east coast signals. Many thanks to Andrew for
sending this picture in!
This is NOT my standard disclaimer.
I love trains, and I love signals. I am not an expert, I'm not a rivet counter. This is something I have fun with while trying to help others.
Although these pages shouldn't be a place for personal opinion, I feel compelled to explain something here, which
many signal purists will not like. I have been "attacked", or
called to task on numerous occasions for using the term "tri-light" for this style, telling me that most signals are tri-lights (because they almost all have three lights), but,
Tri-light in this case refers to the fact that the three lenses are arranged in a triangular fashion.
Others have said I should call this signal a Type G signal, because that is what GRS calls it, but then, Safetran calls it a type V-20R, and US&S a type TR-5/TP-5. Besides, if I called it a Type G
signal, a diehard signal fan (like the ones telling me I should call it a type G) could confuse it with a US&S Type G signal, which is B&O CPL. So I will
stick with "tri-light", much to the chagrin of the signal purists.
Now for some malarky you can skip over unless you want to hear me gripe! :-)
(do you want some cheese to go with that whine?) Having a website for the
educational purposes does put me in the spotlight sometimes, and some people
like Paul (if he is reading this, he knows who he is :-), not just tried to
convince me that I should do something because (to him) it was inaccurate of
just plain out wrong, but he started with name calling and the like because I
wouldn't do what HE wanted. All I can say, is that, as a writer, and
editor, I have the responsibility of being complete. If being complete
means that I have to be technically inaccurate, I will do so, because most
people reading these pages are not die hard professionals that spend their whole
lives dedicated to the design, installation, and maintenance of signal systems.
Even for most of them that do, they understand the need to properly
educate everyone out there who is looking for information. The reader can
then decide for himself what he wants to call something. The other place I
have run into trouble on my 700+ pages is with calling lenses that are a deep
blue in color, cobalt blue. I challenge anyone who has a really, really
strong counter opinion to what I write, to start their own website, and give
away the information for free instead of charging for it as Paul does
Now that all of this hooey is said, you can decide for yourself, is you want to
call these lights: color light signals, tri-light signals, or type G signals.
Whatever you choose, most of us will know what you are talking about.
My philosophy: Pictures and maps are worth a thousand words, especially for railfanning. Text descriptions only get you so far, especially if you get lost or disoriented. Take
along good maps.... a GPS is OK to get somewhere, but maps are still better if you get lost! I belong to AAA, which allows you to get local maps for free when you visit the local branches. ADC puts
out a nice series of county maps for the Washington DC area, but their state maps do not have the railroads on them. If you can find em, I like the National Geographic map book of the U.S..... good, clear, and
concise graphics, and they do a really good job of showing you where tourist type attractions are, although they too lack the railroads. Other notes about specific areas will show up on that page if known.
Pictures and additional information is always needed if anyone feels inclined to take 'em, send 'em, and share 'em, or if you have something to add or correct.... credit is always given! BE NICE!!! Contact info
Beware: If used as a source, ANYTHING from Wikipedia must be treated as being possibly being inaccurate, wrong, or not true.