The 300 Bloor-Danforth bus provides late night service when the subway is not in operation. This service operates frequently along Bloor and Danforth between East/West Mall and Warden. Some trips extend to Pearson Airport, providing late night service in the place of the 192 Airport Rocket. Service is provided east of Warden and Danforth via the 302 Danforth Rd-McCowan bus. On Sundays, these routes operate through the early morning hours because the subway starts at 9:00 am instead of the usual 6:00 am.
Before the subway was built, the TTC operated streetcars from Jane Street in the West, to Luttrell Avenue (west of Victoria Park Avenue) using paired PCC streetcars or multiple units (MUs) from 1950 to the subway line opening in 1966.
The original Bloor-Danforth line was opened in 1966, running alongside Bloor Street and Danforth Avenue from Keele station in the west to Woodbine station in the east. Construction was already in progress to extend the Bloor-Danforth line in both directions, and these extensions opened simultaneously on May 11, 1968, to Islington Station in the west and Warden Station in the east. Until its abolition in 1973, the five stations from Old Mill and Victoria Park outward then formed an anomaly in the TTC's zone fare system, being treated as part of the central Zone 1.
The automated audible announcements for the Bloor-Danforth Line were installed in January 2008, However, while the automated announcements on TTC buses and streetcars are both audible and visible, it is not until the new subway trains that enter service will provide audible and visible automated stop announcements.
The TTC estimates that automatic train control on the Bloor-Danforth Line could be installed by 2020.
Most of the line is underground, with exceptions noted below; most of the tunnel is cut-and-cover, but some is bored. The line generally does not run under Bloor Street or Danforth Avenue themselves, but is offset to the north: in some areas it runs under parks and parking lots behind the businesses on the north side of the street, while other sections run under side streets. All stations except Chester connect to surface TTC bus and/or streetcar routes either by transfer or fare-paid terminal. Other surface and train connections are noted below.
Sections of the line that are not underground are the track between Kipling station and just west of Islington station, from Old Mill station to west of Jane station (this is an interesting case, as the portal at Old Mill station is located at roughly the middle of the platform: the west half of the station is underground, while the east half is on the Humber River viaduct), east of Runnymede station to west of High Park station, east of Keele station to west of Dundas West station, east of Sherbourne station to west of Castle Frank station (although the bridge is covered, and so appears to be a tunnel from the inside), east of Castle Frank station to west of Broadview station (spanning the Don Valley on the Prince Edward Viaduct), and east of Main Street station to east of Warden station (Both Victoria Park and Warden stations are above ground, however they are enclosed).
As per Exhibits ES-14 and ES-15 in the RTES, possible extensions beyond the current western terminus included:
In October 2005, a number of Toronto politicians began a campaign to expand the line northeastward as an alternative for the Scarborough RT, which is heavily used and under constant repair, and to study the viability of this alternative. As of August 2006, this campaign was ended, when Scarborough councilors agreed to support plans to refurbish the existing RT and pursue other RT and LRT options for Scarborough. This is unfortunate as an alternative to develop an independent scarborough subway, connecting the civic centre with downtown Toronto, has yet to be examined.