Unfortunately, the address I have for him may not be any good any more; while I haven't gotten a server bounce from it, I also haven't gotten a reply. The article itself dates back to 1999, even though it was only published in 2010 - it was one of those gems that just needed a little polishing and there was a long period when my ability to provide that polish was ... erratic.
When trying to contact me, don't be too generic in the subject line - I get a lot of spam to the domain account, and if the subject line doesn't specifically name the magazine, a specific version of Traveller, or otherwise have a strong indication that it is a legitimate submission or inquiry, it often gets binned as spam without being looked at. Thus, "Seeking CT Author Neal Oldham" is a better subject line than "contact address wanted".
Also, as a side note, my webhost recently (beginning of the month) decommissioned some servers, but some spam is still flowing into the old mail server. I go in once a week or so to check if anything legit got in there instead of the new servers (which I autodownload); a non-response in that case might just mean that your provider's DNS cache - or your own - needs to be dumped.