James Brennan marked the start of organised harness racing in Western Australia when he called the public meeting that led to the formation of the Western Australian Trotting Association (WATA) in September 1910. Prior to this, the only regular harness racing was conducted at the annual Royal Perth Show.
Meetings of the WATA began at Belmont Park and Claremont Showground in 1911. In 1913 the meetings were conducted at the Western Australian Cricket Association (WACA) ground with night meetings commencing in 1914 - the world's first meetings under electric lights.
Harness racing continued at the WACA until 1929 when a new course was opened under the name of Brennan Park. The name was changed in 1935 to Gloucester Park. Harness racing also commenced at Richmond Raceway East Fremantle in 1928.
Because the pacing gait is generally easier to maintain and easier to teach, the majority of harness races are for pacers. If you've ever seen a pacer racing, you would have noticed a weird collection of straps connecting its front and rear legs on the same side. These straps are called hopples. They can help the pacer balance its stride and maintain a pacing gait. In comparison, trotters do not wear hopples because of their diagonal movement - perhaps this is why they tend to 'break' more often than pacers.
If a trotter or a pacer gallops or otherwise breaks stride during a race, the driver must pull up the horse and coax it back into the approved gait. This is vitally important, because it is unfair to the other runners and is an offence. It is also an offence for a horse not to be raced on its merits. A driver may be reprimanded or penalised by the stipendiary stewards, who supervise the running of licensed race meetings.