Whence the Repeating Signal?

[Mudkip Orange]

In looking at Japanese signalling, primarily Kintetsu in my case, you have (i) Starting/Home/Block signals, which are almost identical to LMS style route signaling, and (ii) Repeating signals, which are PRR position lights in all but name.

 

My question is, how did this come to be?

 

I can see adopting British signalling since the original Shimbashi-Yokohama railway's rolling stock was manufactured in Lancashire. Likewise I can see adopting PRR style position lights since c. 1930s PRR signaling was the most advanced in the world. But how does one arrive at the decision to use *two entirely different signalling systems* with one as a slave to the other? What was the thought process?

[kvp]

 

What was the thought process?

What is the newest technology? LMS signals. Ok, copy them.

A few years later...

What is the newest technology? PRR repeater signals. Ok, copy them, but keep the old signals.

 

This is the same tought process that keept the sailor uniforms in use after the war. In europe, only a few schools use them today (including my old highschool). Many companies never really resignal a whole line or if they do, they usually keep the old standards.

 

Of course the reason could be something simple, that the two types are different enough that noboby would mix them accidentally. A good example are tram signals in Hungary. The official signal type is the normal 2, 3 or 4 color railroad signal, but where the trams run on the streets and drivers could misread a tram signal as a traffic signal, they use dot signals. These show the classic 2 dot signals used on for example PRR dwarf signals, but they are laid out on the masts as the PRR cab signals, with a dedicated lamp lighting each dot pattern.

[westfalen]

I think the repeater signals have nothing to do with Pennsy position lights except in appearance which is only coincidental, the vertical, 45 degree and horizontal lights merely mimic the position of a three aspect semaphore signal.

[katoftw]

Knowing how everyday wiring works within railways now.  Electrical diagrams/schematics have been truly lost many decades ago.  So it is easier to wire up the new system and not delete the old.  As tracing wiring to and from locations 2000-5000 meters apart and/or redoing wiring 2000-5000 meter apart is time consuming and costly, compared to just running it all together, and learning both tyres.

 

Having been in 100s of rural style stations, the dormant wiring from cooper, to phone, to low speed internet, to cable is just crazy.  Now run the decades of changes along 1000s of kilometers of rail corridors, and its easy ti see why the join, not rebuild.

Edited June 5, 2014 by katoftw

[Mudkip Orange]

I think the repeater signals have nothing to do with Pennsy position lights except in appearance which is only coincidental, the vertical, 45 degree and horizontal lights merely mimic the position of a three aspect semaphore signal.

 

I don't buy that, not only is the aspect the same but they both use the same light amber color, which PRR engineers determined was more visible in fog than lunar white. Since the Japanese licensed shot-welding technology from Budd you know their top engineers were already making visits to Philly.

[miyakoji]

you know their top engineers were already making visits to Philly.

I cannot imagine this . These days the expertise would be going the other way.

[ToniBabelony]

Today, travelling to Shinjuku, I noticed Odakyū also uses PRR-style pre-signals: http://livedoor.blogimg.jp/tkchan1/imgs/1/b/1b47bb8a.jpg

[miyakoji]

Wasn't ZOO the most complicated interlocking in North America or the world at one point?

[bikkuri bahn]

Today, travelling to Shinjuku, I noticed Odakyū also uses PRR-style pre-signals: http://livedoor.blogimg.jp/tkchan1/imgs/1/b/1b47bb8a.jpg

Yes, this type, called a chukeishingouki, （中継信号機）, is afaik, the standard on almost all railways in Japan. In underground sections, however, where such a signal would present clearance problems, conventional color light signals are used as repeaters, such as this application on the Hanshin Line