The first locomotive was N°151 Grosvenor, a 2-2-2 with inside frames and cylinders and which was described by Burtt as being the first real express engine to be built by Stroudley. The driving wheels were of 6' 9" diameter whilst the leading and trailing wheels were the same as those of his Class D/D1. The two cylinders were 17" x 24". Outshopped in December 1874, Grosvenor was at first paired with an old Craven tender, then an outside framed one from a class C goods before finally being equipped with a new build tender of her own, which also utilized the D/D1 wheels!

Grosvenor was used until May 1907, frequently on the fast Portsmouth service or the Newhaven boat trains, at which time she was sold to the Italian State Railway having covered some 1,048,090 miles.

The second engine was N°325 Abergavenny of 1876. entering service in 1877 she was a smaller engine than Grosvenor equipped with 6' 6" driving wheels and 16" x 22" cylinders. She also had three tenders, gaining the final Stroudley one in 1885

In 1880 Stroudley brought out the Class G proper, a locomotive that was very similar to N°325, building some 24 of them for use on the lighter Portsmouth services and the Brighton Pullman Limited. They aquitted themselves well in these rôles, indeed some judged them to be better than some of the larger engines that succeeded them! Shortly after their introduction Grosvenor and Abergavenny were officially re-classified as Class G, despite their differences. Locomotive N°329 Stephenson took part in the Stephenson Centenary procession of locomotives at Wylam in 1881. Two others, 335 and 336, were sold to the Italians along with Grosvenor in May 1907.