Wow, that is a very uncommon book. The used book metasearch addall.com shows no copies on the market, and OCLC Worldcat indicates that two libraries hold it, the Smithsonian and the British Library. Interesting problem.
You have several alternatives.
One is to engage the folks at the publisher in some discussion/negotiation
http://www.tpo-seapost.org.uk/ and see if they are in a mood to reprint or move this title to publication on demand.
The other -- and the one I would advise pursuing first -- is to go to a library with which you have some affiliation and have them request an interlibrary loan from the Smithsonian, specially the National Postal Museum, for their copy. It appears to be a circulating book, so you might be able to get it. If they won't loan it in its entirety, then you contact their reference staff (there's an "ask a librarian" form to them on Worldcat at the catalog entry) and get a bit of information about the NY Buenos Aires Line as covered in the book, perhaps even photocopy the two pages for you on a cost recovery basis, etc....
Or make 50 posts and then be at liberty to email a prior poster for the two pages which are an easy fair use case. edited to add: unless you've already gotten a mediated solution to get the two necessary pages....