had been working together on projects since the start of 2017, including a started but stalled system proposed for Canoas. The proposed Accra Skytrain, a five line, elevated light rail network in the capital of Ghana will also use the technology. In 2019 the government of Ghana signed a build–operate–transfer concession agreement with a South African consortium to develop the project, at an estimated cost of $2.6 billion dollars. As of June 2021 the project has not progressed passed the feasibility study stage. In December 2020 it was announced that Aerom, which owns the Aeromovel technology, had been selected to install the GRU Airport People Mover at São Paulo/Guarulhos International Airport. The line will be long and have 4 stations. High Speed Concept Flight Rail Corp. in the USA has developed the concept of a high-speed atmospheric train that uses vacuum and air pressure to move passenger modules along an elevated guideway. Stationary power systems create vacuum (ahead of the piston) and pressure (behind the piston) inside a continuous pneumatic tube located centrally below rails within a truss assembly. The free piston is magnetically coupled to the passenger modules above; this arrangement allows the power tube to be closed, avoiding leakage. The transportation unit operates above the power tube on a pair of parallel steel rails. The company currently has a 1/6 scale pilot model operating on an outdoor test guideway. The guideway is long and incorporates 2%, 6% and 10% grades. The pilot model operates at speeds up to . The Corporation claims that a full-scale implementation would be capable of speeds in excess of . See also Cable railway – a more successful albeit slow way of overcoming steep grades. Funicular – a system of overcoming steep grades using the force of gravity on downward cars to raise upward cars Hyperloop Pneumatic tube Steam catapult – used for launching aircraft from ships: the arrangement of seal and traveller is similar, although positive pressure is used. Vactrain – a futuristic concept in which vehicles travel in an evacuated tube, to minimise air resistance; the suggested propulsion system is not atmospheric. Notes References Further reading Adrian Vaughan, Railway Blunders, Ian Allan Publishing, Hersham, 2008, ; page 21 shows a photograph of L&CR traction tubes unearthed in 1933. Arthur R Nicholls, The London & Portsmouth Direct Atmospheric Railway, Fonthill Media, 2013, ; Story of an unsuccessful attempt at a trunk route