It is a very secret code that you have to answer correctly to join Trainboard. It is used to keep the spammers out. Usually works.
Ummm. It won't work very well if we post it publicly!!! It is exactly for what Russell described. This was put in place because we got to a point where we literally had to have someone sitting here 24 hours, because of the sleaze out there, trying to get in here. They were using an automated software which hit us over and over and over, requiring us to ban dozens and dozens every day. It has made quite a difference, as in the couple of years since this feature was enabled, we have had to weed out less than one dozen scam spammers!