San Marino had a -- regrettably very short-lived -- 950mm gauge electric line: "lower terminus" Rimini in Italy. Opened 1932: badly damaged late in World War II and never restored. (I have a notion that there may nowadays be preservation activity on a very small scale, at the San Marino end.)
Guatemala and El Salvador used to be jointly served by an extensive, and in parts highly scenic, 3ft. gauge system; which connected with the Mexican standard gauge at the Guatemala / Mexico border. This network fell on evil days as from the late 20th century -- underwent some "ups and downs" in status: but all remaining rail activity in Guatemala ceased in 2007, and has not resumed -- lines totally derelict. There might still be a tiny bit of action in El Salvador; but it's reckoned more likely, that all is finished there too.
Nicaragua had a smallish public rail system, on 3ft. 6in. gauge; but that is all now defunct, as from about end of 20th century, I think. I believe Costa Rica is in more-or-less identical case -- 3ft. 6in. there too; am reckoning that I might have heard of some preservation attempt there, or could have imagined that !
Edited to add: Haiti once had public railways -- basically in the form of several short, non-interconnected lines -- all long-defunct. The Dominican Republic had in the past, a bit of public railway (on two separate gauges -- 2ft. 6in. and 3ft. 6in. !), but that is long gone; country might conceivably have something "industrial" still active. Barbados had a public railway, just one route: originally 3 ft. 6in., reduced to ft. 6in. in late 19th century; abandoned in the 1930s. Oh, and still in the West Indies: Jamaica had a standard-gauge public system -- declined in later 20th century, now all abandoned -- last bit closed pre-2000 I think. And Bermuda briefly had a public railway: opened early 1930s I believe, abandoned 1948: all power internal-combustion from the outset.
@Baxenden Bank: sorry -- didn't notice till a moment ago, your entries re Nicaragua and Haiti. Antigua and Barbuda had, I believe, agricultural / industrial lines only; but this thread is taking cognizance of such lines, as well as public ones.