I recently bought this Seiko ‘Railroad Approved’ watch via eBay from a seller in Australia (I’m in the UK).

I searched the internet, and forums, and couldn’t find out much about this particular watch. So I wrote to Seiko UK, who referred me to Seiko Japan. Specifically I asked about which market it was produced for and in what quantity

From Seiko, “Thank you for your patronage of Seiko and your inquiry.
In reply to your inquiry, 7N43-9A00 was…

Seiko Sports 50 – Railroad Approved