Searchlight signals

[Nick_Burman]

Hello all,

 

 

Does anyone have information on the history and the extent of the usage of searchlight signals in Japan? I know that they were used in Hokkaido (last ones were on the Chihoku Main Line, 1994) and on the Shinetsu Main Line, plus on at least one private railway (MIzushima Rinkai), were they used elsewhere and to what extent? Also, I discovered that there were two kinds - mechanical (lenses actuated by cable) and (better known) electric, when and where was each kind used. Also why did JNR give preference to colour light signalling (othter than A, easier to maintain with no moving parts and B, gives more choice of aspects)?

 

By the way...Mark, BB, check this guy out: http://www.lazyjack.co.jp/lazyjack/index.html - his signals are works of art!

 

Cheers NB

[westfalen]

I didn't know the Japanese used searchlight signals, you learn something every day.  I wonder if their use on Hokkaido could be due to the greater American influence in early railway development up there.

 

I have discovered one problem with searchlight signals after installing some on one of my T-TRAK modules.  About a quarter of the club members are colour blind and can't tell what aspect is being displayed.

[Nick_Burman]

I didn't know the Japanese used searchlight signals, you learn something every day.  I wonder if their use on Hokkaido could be due to the greater American influence in early railway development up there.

 

I have discovered one problem with searchlight signals after installing some on one of my T-TRAK modules.  About a quarter of the club members are colour blind and can't tell what aspect is being displayed.

 

According to the Lazy Jack page, searchlights were installed beginning in 1954...so too late for any real US influence.

 

What I was interested to see was the installation on the Mizurin...because of that I'm thinking of adopting searchlights in one part of my (future) layout.

 

Cheers NB

[Mudkip Orange]

Interesting. Does/did Hokkaido have weak route signalling as well?

[miyakoji]

What is weak route signaling?

[Nick_Burman]

What is weak route signaling?

 

Route signalling with some speed-based signalling elements thrown in - see http://en.wikipedia.org/wiki/North_American_railroad_signals

 

As far as I can gather, the Japanese system was plain route signalling, just like the semaphores they replaced.

 

Cheers NB

[miyakoji]

Thanks Nick.  The term "weak" confused me there.  Also, this doesn't have anything to do with the physical form of the signals, but rather what information they convey; I didn't understand that.  I've read about signalling before, it looks pretty confusing.

[westfalen]

 

According to the Lazy Jack page, searchlights were installed beginning in 1954...so too late for any real US influence.

 

What I was interested to see was the installation on the Mizurin...because of that I'm thinking of adopting searchlights in one part of my (future) layout.

 

Cheers NB

 

I didn't see that part, yes a bit late for any US influence.  Could the use in Hokkaido be due to searchlight signals having a more concentrated, visible light in snowy conditions?

 

It is interesting that they were not unknown in Japan, I won't feel so bad now when Japanese trains pass the searchlights on my American modules.

 

BTW I am using these signals by BeNscale.

http://www.benscale.com/

Edited June 21, 2014 by westfalen

[Mudkip Orange]

I've read about signalling before, it looks pretty confusing.

 

There's really three route systems.

 

(i) Speed signaling. In this setup you know exactly how fast to go but you don't know how the switches are aligned. If I'm on the PHL main line approaching a 45mph crossover I will get the same aspect as if I'm proceeding straight but the towerman wants me to go 45 for some other reason. This is common to most US East Coast railroads.

 

(ii) "Strong" route signaling. In this setup the precise route is known but the speed is left to operator knowledge. Typically you need a separate semaphore or signal face for each route. This is the British and Japanese way.

 

(ii) "Weak" route signaling. In this case you know both (i) the speed, and (ii) whether or not you're diverging. But there's only a few speeds, and a "diverging" aspect doesn't tell you what route you'll take once you diverge. This is the western 2/3rds of the US as well as a big chunk of its LRT (which is the result of transit agencies hiring consultants familiar with freight signalling).

 

Searchlights are almost exclusively a west-of-Chicago thing... the rest of the world went directly from semaphores to traffic lights. Certainly I've never heard of them being used for full route signaling.

[westfalen]

The Briitish apparently used searchlight signals more than I thought as well http://www.modelrailforum.com/forums/index.php?showtopic=27562, even had a short section of speed signalling http://www.signalbox.org/signals/lmsspeed.htm. Some photos of some on this preserved railway http://www.embsayboltonabbeyrailway.org.uk/signalli.html.

 

There are prototypes out there for just about everything it seems.

[kvp]

 

Searchlights are almost exclusively a west-of-Chicago thing... the rest of the world went directly from semaphores to traffic lights. Certainly I've never heard of them being used for full route signaling.

As much as i know, they were invented to get around various patents and to have their own unique ones. The first full electric traffic light type signals in hungary were in use by 1896 and the plans to use them were made two years earlier. Of course back then many rural lines used mechanical form signals with gas lights for illuminating the colored lenses. The simplicity of using a single cable for all aspects pretty much ruled out any other types than single and dual arm semaphores. The predecessors of the semaphores were the signboard type signals, that rotated horizontally or vertically to show one of the two aspects. Some had a third aspect showing the edge of the signboard. (typically an all clear were signalled by not showing anything)

Edited June 21, 2014 by kvp

[Nick_Burman]

There's really three route systems.

 

(i) Speed signaling. In this setup you know exactly how fast to go but you don't know how the switches are aligned. If I'm on the PHL main line approaching a 45mph crossover I will get the same aspect as if I'm proceeding straight but the towerman wants me to go 45 for some other reason. This is common to most US East Coast railroads.

 

(ii) "Strong" route signaling. In this setup the precise route is known but the speed is left to operator knowledge. Typically you need a separate semaphore or signal face for each route. This is the British and Japanese way.

 

(ii) "Weak" route signaling. In this case you know both (i) the speed, and (ii) whether or not you're diverging. But there's only a few speeds, and a "diverging" aspect doesn't tell you what route you'll take once you diverge. This is the western 2/3rds of the US as well as a big chunk of its LRT (which is the result of transit agencies hiring consultants familiar with freight signalling).

 

Searchlights are almost exclusively a west-of-Chicago thing... the rest of the world went directly from semaphores to traffic lights. Certainly I've never heard of them being used for full route signaling.

 

In the case of ii, speed for the straight or diverging routes might be displayed in boards ste next to the track. Japan does do that.

 

The Delaware & Hudson used searchlights; I think Boston and Maine was also a searchlight user.

 

Cheers NB

[bikkuri bahn]

Nick, some internet search turned up a little more information.  Searchlight signals are called tantoushikishingouki (単灯式信号機).  They were (first?) installed on the Shin-etsu Line, and were also extensively used in Hokkaido, perhaps due to their small profile being an advantage in heavy snow regions.  In general, their application was on non-electrified single-track mainlines, and secondary main lines  (such as a cross-country route like the Chihoku Line, I reckon). With the revision of the signaling basic equipment standards in 1965, searchlight signals were no longer specified for installation, leading to their decline/replacement.  I have also seen pictures of these signals on the Kansai Main Line in the mountainous areas, a line consistent with the above guidelines.

*also the Fukuchiyama Line, pre-electrification

Edited June 23, 2014 by bikkuri bahn

[Mudkip Orange]

In the case of ii, speed for the straight or diverging routes might be displayed in boards ste next to the track. Japan does do that.

 

IIRC every RR with strong route signaling considers the posts to be "reminders" and ultimate responsibility rests with the driver. e.g. if a storm blows down the little "30" placard and the driver hits it at 70 the driver is still at fault.