Head and Tail Lamp and Disc Codes of Meiji era Japanese Railways

[SL58654号]

I was drawn to this illustration in Dan Free's Book "Early Japanese Railways" featured in the appendix. It does not have much context elsewhere in the book, but curiosity has made me ask:
Was this applicable to any of the other private railways as well (Sanyo, Nippon, Kansai, etc.) and were the discs always either green or red? Meiji mura's demonstration line seems to have reds discs only. 
I've noticed in many builder's photos that engines supplied from US builders for Japan often came equipped with marker lamps similar to those on UK locomotives. Like these lamps on this brass 8550 model. Or this 6400 model. Gosh, aren't these oldies but goldies? 

Edited January 16 by SL58654号

[Beaver]

Given that the Nippon shared the line between Ueno and Omiya with the IJGR I would think they would have had to use the same lamps, discs and codes for safety reasons. There is also the consideration of why a company would come up with it's own system rather than copy one that worked unless there were significant operational differences to account for.

 

Seeing as the green disks are apparently only for extras then it makes sense that you don't see them on a museum line. The distinction between scheduled and extra services doesn't really exist when you are running one train only over very short distances.

[SL58654号]

2 hours ago, Beaver said:

Given that the Nippon shared the line between Ueno and Omiya with the IJGR I would think they would have had to use the same lamps, discs and codes for safety reasons. There is also the consideration of why a company would come up with it's own system rather than copy one that worked unless there were significant operational differences to account for.

 

Seeing as the green disks are apparently only for extras then it makes sense that you don't see them on a museum line. The distinction between scheduled and extra services doesn't really exist when you are running one train only over very short distances.

Many thanks. I really admire the multitude of head code discs seen on pre-grouping railways in Britain, with the crosses, plain white discs etc.
Japan is one of the few places elsewhere I know of that seemed to utilize a similar method. 

[Beaver]

On 1/16/2024 at 2:45 PM, SL58654号 said:

I really admire the multitude of head code discs seen on pre-grouping railways in Britain, with the crosses, plain white discs etc.

 

Markings on the discs turned out to be a bad idea. Using the number and positions of the disks to determine the code was much easier to see from a distance and much less likely to be misread (sun glare on a disc obscures the markings, etc). Additionally a brightly painted unlit lamp is almost as easy to see in the daylight as a disk and saves having to keep two sets of markers for day and night.