Complex sentence: Between 1894 and 1904, four similar engines were built by Baldwins for the WMR, and in 1908, these became Na and Nc classes, with two units each.
Split into simpler sentences: Between 1894 and 1904, four similar engines were built by Baldwins for the WMR. In 1908, these became Na class and Nc class, with two units each.