The Type ZA tender entered service in 1892, as tenders to the first batch of 7th Class 4-8-0 Mastodon type steam locomotives to be acquired by the Cape Government Railways.

[1][2][3] The Types ZA and ZB tenders were both introduced in 1892 as tenders to the original Cape Government Railways (CGR) 7th Class 4-8-0 Mastodon type locomotive, which was built in two batches.

Since a Neilson works picture shows one of the Neilson-built batch of locomotives with the larger-capacity three-axle Type ZB tender, it is likely that the smaller-capacity Type ZA bogie tenders were delivered with the first batch of six 7th Class locomotives, built by Dübs.

[1][2][3] The Type ZA entered service as tenders to these locomotives, all of which were initially placed in service on the Midland System of the CGR, but were later distributed between the Midland and Eastern Systems.

These engines would be designated Class 7 on the South African Railways (SAR) in 1912.