(n)the nature, dimensions, fittings, appliances and apparatus of the carriages to be used on the tramway, and the inspection and examination thereof by officers of the [Government] [Substituted 'Local Government' by the A.O. 1937.] or the local authority, and the liability of the promoter or lessee, on the requisition of the [Government] [Substituted 'Local Government' by the A.O. 1937.], from time to time, to adopt and apply such improvements in the carriages, and in the fittings, appliances and apparatus, as the [Government] [Substituted 'Local Government' by the A.O. 1937.] may consider necessary or desirable for the safety or convenience of the public;