Identifying Railroad On 1908

Here is a 1908 cover, with an RPO postmark (is it called a CDS when its an RPO?). I can't identify the railroad, "Rock. and Portland". The Portland is probably Portland Maine. The name on the left edge 'John W. Richardson, Damariscotta Mills' suggests Rockland or Rockport, but I can't find a reference to either, nor can I find a reference to Rockingham and Portland RR. Anyone interested in Maine or RPO covers have an idea of the railroad name?

By the way, thanks to the folks who responded to my query yesterday about the Cuba to Charleston SC to Portland Maine cover with pair of US63 stamps. It was very helpful and I would have thanked you in the string for that topic, except I couldn't figure out how to do so.

The circular cancel by itself is still called a CDS, usually referred to as a CDS Railway cancel, however, with the oval to the right, I think this is an RPO duplex cancellation (?)

Chimo

Bujutsu

Rock Island Railroad??

Thanks, I don't think it's Rock Island Railroad.

Maybe this might be your railroad?
http://en.wikipedia.org/wiki/Rockland_Branch

I think you're looking at Rockland and Portland RPO, part of the Maine Central Railroad, as shown on this map and post office RPO list:





Also, if you want to look up New England RPO's, this is a good resource to start with:

http://www.faracresfarm.com/jbvb/rr/ne_mail.html

The 'Reply To Topic' link at top or bottom of page is the one to use. This adds on to the presently viewed thread or string.

Thank you. I believe that spain_1850 and wt1 nailed it. Bujutso, thanks for the info on terminology, and lastly, puzzler, thanks for pointing out what I should have seen on my own.

Also, the RMS in the oval killer cancel stands for Railroad Mail Service.