Class QBL was the final derivative of the bolster wagons dating back to the original class Q of the 1890's. A total of forty of these wagons were created by modifying QBB class bolster wagons in 1973 (1674, 1692, 1713, 1763, 1774/6, 11788, 1881, 2220, 2857, 2863, 2900, 2970/3, 3297, 3308, 3324, 3378, 3384, 3432/7, 3518, 3524, 3544/6, 3565/9, 3576, 3585/8, 3593/5/8, 3600, 3646, 4669, 4769, 4771, 4782, 4826)

1975

2220, 3569 written off

1983

1776, 2970, 3576, 3593/8, 3646, 4669 written off

1976

2863, 3324, 3524 written off

1984

1788 written off

1977

1881, 3384, 3437, 4826 written off

1985

3585 written off

1978

1674, 1763, 2973, 3308, 3432, 3518, 3588 written off

1986

1692 written off

1979

1713, 2900, 3297, 3378, 3544, 3565, 4769, 4771 written off

1987

1774 written off

1980

3595, 3600, 4669, 4782 written off

1990

3546, 4782 written off

1981

4669, 4782 written back

1991

2857 written off