I think she's the 'City of Simla', used on both the City Line's Indian services and Bucknall's South African service. Built by Wm. Gray & Co. at West Hartlepool in 1921, 9,468GT, 476' x 58', twin screw, turbines, 13 1/2 knots. about 260 passengers.
Torpedoed and sunk in September 1940 50 miles off Malin Head.
The number of boats is a puzzle--many more than would be needed in regular service and more than are shown in other photos of Ellerman passenger liners.
I found one other vessel, the earlier Ellerman Hall liner 'City of Marseilles', that was of very similar appearance to the 'City of Simla'. She was used as a part time trooper to India during most of the twenties and that would account for the extra boats.
If you enlarge the picture, it looks as if there may be more than the normal 200-300 or so passengers onboard.
Built by Palmer on the Tyne, 1913, 8,250GT, 469' x 57', twin screws, 4exp, 13 knots.
Pictures of both ships:
I'd bet on the "Marseilles".
The counter stern on the "Simla" threw me.
The 'City of Exeter', 1914, built a year after the 'City of Marseilles' began the Ellerman cruiser stern passenger liners and the 'City of Simla', appears to be a throwback to earlier times.