T-Mat

T-Mat - also known as T-Matter (PROSE: Second Session) - was a transmat network that had been established on Earth by the mid 21st century and was run by Travel-Mat. (TV: The Seeds of Death) A few decades after the year 2025, T-Mat fought an "intellectual copyright battle" with iTeleport. (PROSE: Horror of the Space Snakes)

The technology was invented by Florian Hart's father. (PROSE: The Wheel of Ice) T-Mat cubicles were used as a reliable and cost-effective means of mass-transporting goods all over the world.

The development of T-Mat ultimately led to the abandonment of manned space programmes, with the only launch vehicles remaining being those required to place satellites in terrestrial orbit. It apparently never occurred to anyone in charge that the transmat link between Earth and the moon might one day catastrophically fail beyond the capacity of the moonbase personnel to repair. The Ice Warriors exploited this weakness when they took over the base as a beach-head for their ill-fated invasion of Earth; a corollary of this compromise of the network was a disastrous collapse of global food distribution. (TV: The Seeds of Death)

T-Mat also saw the abandonment of trains, road and air transport since it was instantaneous - people who continued with such forms of transport were considered eccentric. (PROSE: The Seeds of Death)

In the aftermath of the invasion and the Thousand Day War, the T-Mat network was replaced by the Interstitial Mass Transit System. (PROSE: Transit)

One account claims some scientists, Froyn and Rhynmal, working for the Space Security Service in the year 4000, were working on a molecular dissemination experiment to increase the distance of travel allowed by the T-Mat system. (PROSE: Mission to the Unknown)

Members of the Scarlet Guard wore small T-Mat units on their belts, which they used to travel around Hyspero. (PROSE: The Scarlet Empress)

Mombassa Station had a T-Mat station. (AUDIO: Race Memory)

Legacy
A leaflet advertisement was used as evidence in the Second Doctor's trial. (PROSE: Second Session)

Behind the scenes
According to The Brilliant Book 2012, a book that contains non-narrative based information, history would remember the T-Mat as causing the end of the First Great and Bountiful Space Race.