Works well (see last photo). 5 Jewel Seiko 75 series movement - same as 7548A and 7549A Seiko dive watches. This is an example of the first quartz railway watch introduced by Seiko in late 1977.
This is an early one made in February 1978. More, very interesting, information on the railway watches and their use can be found here. To make sure the watch keeps good time, it was set up on a quartz tester. The spec for this movement is.The final photo shows the measurement. Around 0.2 sec/day is 6 sec/month. As the watch is not thermally compensated this will not hold for all conditions. The point of the test is to show that not only is the watch running, it is also running well with great accuracy.
This watch shares the same quartz circuit (and similar movement) as the Seiko 7548 and 7549 dive watches. The circuit board bears the 5 jewel designation. It would require a swap of the circuit cover which in this case is marked 7550A.
Never had the need to delve that far. This is a watch in used cosmetic condition. Wear and marks on the caseback from use.The crystal has no obvious marks or scratches. Please examine the photos carefully. Battery age unknown, but tests OK. The time sets as it should. These movements are adjustable and are capable of very high accuracy. I do not know the service history of the watch. You should assume it will need a service at some point. Overall a very good usable watch. Included in this listing is the watch itself with the lanyard. The package will weigh under 0.25kg so the following rates will apply. UK, France, Spain, Sweden etc. Taiwan, Hong Kong, Singapore, Japan, South Korea inc. If your country is not listed please ask. No tracking unless indicated (Canada only). Elsewhere in Canada, just the GST/HST as appropriate. Let me know if you have any concerns. Any other questions, please ask. The item "Seiko Quartz Railway Pocket watch 7550-0010 7550A 7548A 7549A movement 1978 511" is in sale since Tuesday, July 7, 2020. This item is in the category "Jewelry & Watches\Watches, Parts & Accessories\Watches\Wristwatches". The seller is "jmvanauto" and is located in Victoria, BC. This item can be shipped worldwide.