The last new open wagons built for the M.R.W.A. were the 100 PB class wagons numbered 1001-1100 built in 1962. They were identical to the W.A.G.R. KA class and in 1964 when the M.R.W.A. was taken over that is what they were reclassified as. Reclassification and disposal of these wagons was as follows:

1964	PB1001-12, 1014-8, 1020-5, 1028-46, 1049, 1051-75, 1077-92, 1094-1100 to KA40001-12, 40014-8, 40020-5, 40028-40046, 40049, 40051-75, 40077-92, 40094-40100.
1965	PB1013, 1019, 1026, 1027, 1047, 1048, 1050, 1076, 1093 to KA40013, 40019, 40026, 40027, 40047, 40048, 40050, 40076, 40093
1975	40047 written off
1976	40023, 40033, 40064 written off
1977	40006, 40035 written off
1978	40041 written off
1979	40052, 40075, 40081 written off
1980	40025 written off
1982	40025, 40081 written back
1983	40083 written off
1984	40046 written off
1986	40020, 40026, 40034, 40037, 40043, 40054, 40057, 40058, 40065, 40086, 40091, 40092 written off
1987	40005, 40017, 40028, 40053, 40056, 40068, 40082, 40085, 40099 written off
1989	40010, 40013, 40018, 40019, 40029, 40036, 40048, 40049, 40051, 40061, 40062, 40067, 40072, 40074, 40077, 40084, 40087, 40094, 40098 written off
1990	40001-3, 40007-9, 40011, 40012, 40014-6, 40021, 40022, 40024, 40025, 40027, 40030-2, 40038, 40039, 40040, 40042, 40044, 40045, 40050, 40055, 40059, 40060, 40063, 40066, 40069, 40070, 40071, 40073, 40076, 40078, 40079, 40080, 40088, 40089, 40090, 40093, 40095-7, 40100 written off
?	40004 possibly November 1990 when all remaining KA written off?