the 252 hp CNG engine or model 6 AP 1400 B for the 299 hp diesel engine). Previously available was the Voith D864.3E 4-speed automatic transmission as well as the ZF Ecomat 5 HP 502/592 5-speed and 6 HP 502/592 6-speed automatic transmissions. Orders Australia Large numbers of buses built on the OC 500 LE chassis can be found in Australia, where it was originally marketed as the O 500LE. then got renamed as the Mercedes OC 500 LE . Now, it is marketed here like in the world, as OC 500 LE. Transperth operate 540 Volgren bodied examples, 474 being CNG powered. There have been 15 OC 500 LE CNG fires in Perth, and in October 2013, the Public Transport Authority commenced legal action against Mercedes-Benz, Evobus and Volgren. The action was dropped in 2014. Sydney Buses purchased 255 CNG and 20 diesel powered examples, all with Custom Coaches bodies, however one was destroyed by fire in June 2011. The Custom O500LE is powered by a 185 kW and 1050Nm CNG M 447 hLAG inline 11.967 litre 6-cylinder engine. There are two gas tanks (indicated by two CNG stickers on number plate) located on top of the bus near the front. Metal pipes run on the offside roof to the back of the bus. Because the gas tanks are in the front, the air conditioning unit is placed at the rear of the roof. The gas tank placement is counter-intuitive, but this is due to the various weight requirements imposed by the RMS. Other purchasers included Ventura Bus Lines (72), Brisbane Transport (40), Premier Illawarra (38), Kefford Corporation (19) and Darwin Bus Service (14). Many operators across Australia have now purchased the OC 500 LE in various configurations. Problems related to quality control and unreliable electronics have not been uncommon. A lot of these complaints have come from drivers due to some units being under-powered, uncomfortable or rough. Brisbane Transport withdrew its OC 500 LEs from the fleet for a short period because of a major unidentified fault which caused buses to suddenly accelerate without warning. This problem was fixed by Mercedes-Benz and these vehicles are now back on the road. However, as they were under lease from Mercedes-Benz, their lease expired in 2013 and were then sold to Transit Systems NSW where they currently operate. In January 2009, Mercedes-Benz Australia issued a recall on 443 CNG-fuelled OC 500