Accutron Railroad Approved, 2182 movement, metal case. Date only with Arabic numerals and red 24 hour Arabic numbers. The case back inside has some very feint text about battery replacement and what looks like the number 2662. There is also some hand scribed text which looks like 23 followed by a triangle symbol followed by WM3880, the M could be a Y. There is no date or serial number on the movement or jewel count. The case has M7 under the serial number.
It's a good question. Accutron Calendar models house a 2181 (2181F, 2181G), whilst Accutron Day & Date models housed the 2182 (2182F, 2182G)
Your movement may not be original to the watch, but I gather still works well with a 2181 replacement.
I was not able to find a case match in Darold Hanson's complete guide to Bulova Accutron watches. There are a few Accutron Calendar 'Railroad' versions listed.
Generally speaking I would ID this as a 1967 Bulova Accutron Calendar, as the linebooks (and the guidebook) do not label any of them as Railroad models.