In 1970 fifteen WSH class standard gauge ballast hoppers numbered 30501-30515 were converted to class XM. In 1972 30501 was temporarily converted back to WSH as were 30502/45/6/8/9, 30510-2/4/5 in 1981.

Four of these hoppers were modified to carry gravel ballast by ARG and reclassified XMG (30501, 30502, 30503 and 30505).