Construction of Knostrop Sewage works was begun in 1875 by the Corporation of Leeds. The works was a success, indeed several more precipitation tanks were added in 1897. From 1898 until 1906 the works had a reputation as a research center for sewage processing and disposal.

When built, Knostrop Sewage Works was surrounded by standard gauge railways. The Midland line was against the southern side of the site, whilst the Great Northern was on the west and the Waterloo Main Colliery branch looped around the north of the site. At the west of the site, standard gauge sidings were provided, these were connected to both the Great Northern & Waterloo Main branch lines. A 4 wheel MotorRail (wn 3676)was provided to work these sidings, this locomotive began life as a 'Protected' WW1 60cm gauge MotorRail (original wn 1290) - indeed the same as the engines depicted above.

In 1908, when the sewage works was extended again. As part of this extension an extensive 60cm narrow gauge 'tramway' (railway) was provided, initially on the low level site, but the extended to the upper works site. Initially a small Hunslet 0-4-0T "Microbe" was provided (wn 1028) in May 1910, this was supplemented in December by a Hudswell Clarke built 0-4-0T "Bacillus" (wn 931). A fleet of new Robert Hudson built rolling stock was purchased at inception. The typical duties for the railway system would be taking sewage sludge, or pickings from the detritus tanks (paper, rags, leaves, etc) to the tip.

A shift in policy after WW1, saw a change in motive power for the narrow gauge railway system. The two steam locomotives were sold, "Microbe" went to the Leeds Sand & Gravel Company in 1922, whilst "Bacillus" went on to A. R. Briggs & Co, Leeds to their Newlay Quarry. Their replacements came in the form of 2 former WW1 'Protected' MotorRail locomotives.

These engines are believed to have never seen active service in France, being delivered new (in 1918) to the War Office supply dump at Purfleet, from where they are reputed to have been bought by Fowler of Leeds. These two engines arrived at Knostrop in 1921. In 1935 they were joined by a 4-wheel mechanical loco built by James C. Kay Ltd of Bury, unfortunately it was scrapped in 1965.

The last narrow gauge locomotive to arrive at Knostrop was a Ruston 4-wheel diesel mechanical LBT class, built & delivered in 1960. Unfortunately this locomotive suffered some major engine damage, and by 1979 was observed to be out of use pending a decision on its future. The "Protected" MotorRail locomotives continued in service for another year or so.

The Ruston was eventually sold to John Craven of Notts in 1981, who subsequently sold it on to C & D Lawson who now have it stored on a private site (no public allowed) in Nottinghamshire. MotorRail No 1 (MR1369) was moved in April 1981 to Armley Mills Industrial Museum, Leeds for preservation. Subsequently this engine moved on loan to the Moseley Railway Trust where it has been returned to working order. MotorRail No 2 (MR1377) was eventually acquired by the National Railway Museum. It was transferred to the Leighton Buzzard Light Railway around 1995, who have restored it to working order.