According to Wikipedia, they are still used in Canada on Vancouver Island, and a few in Ontario, with some cars to be refurbished for additional expanded VIA rail service in Ontario. Also, TRE from Dallas to Ft Worth, and Cape May Seashore Lines (tourist).
The Reading & Northern in PA owns a couple, but according to their site say they are "down" with no immediate plans of restoration.
Here are 3 photos I took, one along the Reading (now SEPTA) at Bethlehem in 1978, and two from the British Columbia Railways
(ex-Pacific Great Eastern) North Vancouver shops in April, 1975, when they were still running.
They were definitely the way to go for branch line service while they lasted, it would have been great if they had kept up with the concept. Of course in earlier days, especially back in the 20's & 30's there were other types of flanged-wheeled "jitneys" as well, like the 1925-era M-100 and 1935-era M-300 seen here when I visited the California Western in 1974 (operating those cars as well as steam for tourists).