Editing Key System (section)

=== Transbay rail lines ===
[[File:1941 Key System map.jpg|thumb|1941 Key System map with a detail of the Transbay Terminal]]
{{Key System|collapse=y}}
Until the Bay Bridge railway began operation, Key commuter trains had no letter designation.<ref name=Demoro189-190 /> They were generally referred to by the principal street or district they served, though the Key System did not have any formal naming scheme outside of letter designations.<ref name=Demoro189-190 />
{| class=wikitable
!Line
!Name
!Notes
|-
|style="text-align:center"|A
|[[Downtown Oakland]]
|Was extended to 105th Avenue [[East Oakland, Oakland, California|East Oakland]] to near the [[San Leandro, California|San Leandro]] border on the East Bay Transit Company tracks along 14th Street in March 1941. Less than two weeks later in early April, the line was rerouted on its outer end over former Interurban Electric Railway trackage along Bond Street to Havenscourt.<ref name=Demoro104 /> Cut back to 12th and Oak in Oakland on October 29, 1950.<ref name=Demoro126>{{harvnb|Demoro1|1985|p=126}}</ref>
|-
|style="text-align:center"|[[B (AC Transit)|B]]
|Lakeshore and Trestle Glen
|Originally ran through a Key hotel, the [[Key Route Inn]] at Grand and Broadway in Oakland; the Inn burned down in the 1930s.
|-
|style="text-align:center"|[[C (AC Transit)|C]]
|Piedmont
|Via 40th Street and [[Piedmont Avenue, Oakland, California|Piedmont Avenue]]; alongside Pleasant Valley and Arroyo avenues; and between York Drive and Ricardo Avenue to terminus at Oakland Avenue. Originally terminated at Piedmont Avenue; extended to Oakland Avenue on November&nbsp;21, 1924.
|-
|style="text-align:center"|[[E (AC Transit)#History|E]]
|Claremont
|Ran directly to the [[Claremont Resort|Claremont Hotel]], terminating on a track between the two tennis courts; the tennis courts survive to this day
|-
|style="text-align:center"|[[F (AC Transit)|F]]
|Berkeley / Adeline Street
|Extended on former Southern Pacific interurban tracks on [[Shattuck Avenue]] beyond Dwight Way and through the SP's [[Northbrae Tunnel]], terminating at [[Solano Avenue]] and The Alameda
|-
|style="text-align:center"|G
|[[Westbrae, Berkeley, California|Westbrae]] Shuttle
|A streetcar shuttle providing a connection at University Avenue with the H transbay train. Replaced with bus service on July 26, 1941.<ref name=Demoro104>{{harvnb|Demoro1|1985|p=104}}</ref>
|-
|style="text-align:center"|H
|Monterey Avenue
|Originally known as the Sacramento Street Line, the original line ran up Hopkins, but was switched to the SP's old tracks up Monterey after 1933. Replaced with bus service on July 26, 1941.<ref name=Demoro104 />
|-
|style="text-align:center"|K
|College Avenue
|Streetcar shuttle providing a connection at Alcatraz Avenue and Adeline Street with the F transbay train. This line ran extra cars and was heavily used on football game days as its terminus was only a few blocks away from UC's Memorial Stadium. Replaced with bus service on September 30, 1946.<ref>{{harvnb|Demoro1|1985|pp=122}}</ref>
|-
|}
D was reserved for a proposed line into [[Montclair, Oakland|Montclair]] alongside the [[Sacramento Northern]] interurban railway.<ref name=Demoro189-190>{{harvnb|Demoro2|1985|pp=189–190}}</ref> Shortly after opening of the Bay Bridge to train traffic, the Key System continued to use its pier for special service trains for ferry service to the 1939 [[Golden Gate International Exposition]] on Treasure Island{{nbsp}}— these were given the special designation "X". The service was discontinued at the end of the first year of the Exposition and not revived for the 1940 season.<ref>{{harvnb|Demoro2|1985|pp=100–103}}</ref>

On September 13, 1942, a stop was opened at Yerba Buena Island to serve expanded wartime needs on adjacent Treasure Island.<ref>{{harvnb|Demoro1|1985|pp=111}}</ref>  It remained after the war until the end of all rail service on the Key System.

The A, B, C, E and F lines were the last Key System rail lines. Train service ended on April 20, 1958, replaced by buses using the same letter designations. AC Transit preserved the letter-designated routes when it took over the Key System two years later, and are still in use; AC Transit's B, C, E, F, G and H lines follow roughly the corresponding Key routes and neighborhoods.