route. Trams Lothian Buses' services have been integrated with Edinburgh Trams, since the trams commenced operation in 2014 – both are managed by Transport for Edinburgh, with Lothian Buses serving interchange with the trams at various locations. The now closed guided busway element of Fastlink formed part of phase 1a of the tram permanent way. Fleet Edinburgh Corporation and Lothian Buses have historically employed a high degree of standardisation of their service bus fleet, including the use of low-floor buses to facilitate maintenance savings. Lothian have never employed minibuses on their services, although some midibuses were used for a time. As of December 2019, the Lothian fleet, including East Coast Buses, Lothian Country, the Edinburgh Tour and Lothian Motorcoaches, consisted of 900 buses. Current vehicles Lothian first introduced low emissions vehicles in the form of hybrid buses into service in 2011 with the purchase of 15 Alexander Dennis Enviro400Hs; these were subsequently retrofitted with diesel engines in 2018 due to issues with the hybrid batteries. These were supplemented with the arrival of the first ten Volvo 7900Hs in April 2013, initially allocated to route 1 from Clermiston to Easter Road. 20 more of the type were delivered in July 2014, followed by the delivery of another repeat order for 20 at the end of the year. In 2017, Lothian Buses introduced six Wright StreetAir battery electric buses for route 1, replacing the Volvo 7900Hs. Another five were planned to be purchased in 2018 to fully electrify the route, but the order did not materialise. These were later complemented by four Alexander Dennis Enviro400EVs in March 2021, purchased with funding by Scottish Power and the first battery electric double-decker buses to be purchased for Edinburgh. Historically Lothian has purchased new buses for its regular services across Edinburgh, however in 2018, the company purchased 50 Wright Eclipse Gemini 2 bodied Volvo B9TLs from Tower Transit and Metroline, which were heavily refurbished before the first of the batch entered service in April. In November 2018, the company announced the purchase of 42 13.4m Alexander Dennis Enviro400 XLB bodied Volvo B8L tri-axle buses, the first batch being delivered in early 2019, in time to celebrate the 100th anniversary of the founding of the company. The vehicles have 100 seats, with front and centre doors. Another batch of these buses, branded in a dark blue and gold livery for the 'Airlink' 100 express service, were