This model was made by Seiko from 1972 until 1978. Some of them are found with specific Japanese railroad property markings engraved on the back. This one has no markings. After 50 years (+ or -) it's keeping very good time.

It is basically a hack watch, the time stops when the crown is pulled for setting. Lots of shock proof cap jewels!

For more information about Seiko railroad pocket watches, this is very useful:

Plus9Time
SEIKO, CITIZEN AND OTHER JAPANESE WATCHES

An excellent post, thank you.

I’ve been watching these come and go in eBay and they seem to go for good money!

Reg! Mark