Why is that at Train Signals Red is at the bottom whereas in Road signals Red is on top?

Question

I think this question applies in all countries.

Answer 1

Yes, and no.

In the US there are several types of signals.  Some of the signals are a single "Target" that changes its color.

Some are directional even for trains.

But the answer to your question, is so they are not confused with standard traffic signals when they are located near traffic intersections.

In my area, (San Jose), Union Pacific main-line runs next to a road called Old Monterey Highway, (Old Route Hwy. 101), between South San Jose and Morgan Hill.

All of the signal stands in this particular location are of the songle target type I mentioned earlier, until you get into a little community called Coyote.  There a road crosses the main-line, and the signal stands are of the type you mentioned, with the green being on the bottom.  

I asked the same question of a couple of my club members a while back, and if memory serves me correctly, that was what they stated at the time.

Good Luck, and don't forget, Stop, Look and Listen.

Answer 2

In Ireland I have heard the traffic lights have green on top because they dont think any color should be over green.

I can"t say for sure,  I have never been to Ireland.

I'm going out on a limb here but a common reilroad expression for go, or go fast or go without restrictions is "highball"

There was a very primitive signal system where colored balls were raised or lowered by ropes and a pulley system, and when the proceed signal was on top, it was a "highball"

So from the very early days of railroading, the non-restricting proceed signal was always on top.

Whey highway and roadway signals use a different system is a mystery though, I am sure someone knows, will be interesting to see.

Answer 3

for roads, red can be on the top when mounted vertically OR at the left if the signal is mounted horizontally.  different jurisdictions around the world have different preferences as to how to even mount the traffic signal.  even different states/provinces within USA or Canada have different preferences.

originally, red and green colours were used for shipping signals (ie, starboard and port sides).  railroads adapted those colours later when they needed signalling.  railroad signals started off with lanterns and flags, upgraded to semaphores, and eventually upgraded to electric signals before 1900.

  the first traffic signal seems to be in london in 1869, but it used fuel and it exploded one day.  later, in the 1910s and 1920s, road traffic lights were adapted from railroad signals.  most were electrical, but not all.

some railroad signals used different systems too, not everyone used red/green.  the most famous example is the Pennsylvania Railroad, which used a circular 8-aspect amber light system instead.  the patterns of lights would denote different things to the engineer, but all the lights were always amber/yellow.

syracuse ny in 1920s used green over red.

offhand i cant find a specific reference yet as to why the road traffic signals were done in reverse from railroad signals.  i just know that as a transport planner, i have to follow the MUTCD and FRA rules for the various signaling systems depending on road, rail, bike, pedestrian, and others. and this is the way that the rules are written.

i would concur tho' that at the time of the the traffic signal appearance in the 1920s, that many streets/roads were nearby or parallel to the existing railroads, and that it probably was logical to avoid confusion by auto drivers and to keep them from using railroad signals in error while they were driving.  many of the new drivers were not professionals, and there were no licensing schemes in the early days of the car, so anyone who had access to a car could be out driving it, without knowing "rules of the road" bcs they either didnt exist or were just extensions of the courtesies already in use for horse and buggy, streetcar/trolley, etc.

it wouldnt be as important for the locomotive engineer, as the engineer could not steer the train anyway if he tried using an auto signal, can only stop and go with the train.  and the loco engineers would have extensive training on their rail system and already know where the proper rail signals are at and the geography of their rail - even to this day, engineers can not drive until they "qualify" by learning every detail of the railroad that they are running on.