Throughout the period of the broad gauge, passengers were carried in three classes of carriage. Until 1844, passenger trains only conveyed first and second class passengers. Third class passengers were conveyed in open carriages attached to goods trains. The Railway Regulations Act 1844 required railways to provide third class travellers with closed carriages and to be conveyed by at least one passenger train each day, stopping at all stations, at an average speed not less the 12mph. Express trains, however, continued to cater only for first and second class passengers for many years afterwards.
Broad gauge carriages differed from their standard gauge counterparts in two areas. Firstly the wheels on broad gauge carriages were 4ft (1.23m) in diameter compared to the normal 3ft 6in (1.08m). Secondly, apart from a brief period in the 1860s, passenger's luggage was not carried on the roof of the carriages. Both these features enabled trains to operate at faster speeds. However, despite the increased width of the gauge, broad gauge carriages were not significantly wider than those on standard gauge railways.
The initial "Posting Coaches" for first class passengers had four wheels and carried 18 passengers. The design was not suitable for higher speeds and all but three had been withdrawn by 1849. Six-wheel carriages soon replaced the early stock and the general design did not alter for the life of the broad gauge. First class carriages were 24 ft (7.4m) long and had four compartments, each seating eight people on padded seats. At night two, later four, oil lamps would be put in the special roof pots to provide lighting. After 1854, most six-wheel carriages were built as composites, with two first class, two second class and one luggage compartment.
Six-wheel second class carriages were slightly longer at 27 ft (8.3m) and were divided into six compartments each carrying 12 (10 after 1854) passengers on wooden seats. Unlike the first class carriages, these carriages were equipped with a manual brake which was operated by a guard who sat with the passengers. Prior to 1844, these carriages had open sides and were the subject of much complaint, even from a public used to travelling outside on stage coaches. When the Railway Regulations Act 1844 improved the facilities for third class passengers, these second class carriages were improved, and windows were installed to cover the open sides. It was not until 1860 that padded seats were provided for second class passengers.
The first third-class carriages were little more than four-wheeled open trucks with wooden benches. Third class passengers were only conveyed by goods train until 1844, when it became compulsory for railways to provide passenger trains for third class travellers. To comply with the new regulations, the Great Western Railway designed six-wheel wooden vehicles with small ventilation louvres rather than windows. These carriages carried 59 passengers and a brakesman. The design changed in 1848 when new third class coaches were made almost entirely of iron with small windows in the door. After 1856 no new third class broad gauge carriages were built and older second class carriages began to be used for third class passenger traffic. However, a number of the iron carriages survived until 1871. At night, a single oil lamp was provided for the entire carriage.
In 1852 eight-wheel composite carriages were introduced for the London to Birmingham expresses. The carriages (nicknamed "Long Charleys") were 38 ft (11.7m) long and were divided into seven compartments - three first class, carrying eight passengers each, and four second class, carrying 12 passengers each. When broad gauge services to Birmingham ceased in 1869 these carriages were used on the Metropolitan Railway and on London local trains for a few years before being broken up in 1875-7.