T1 (Lancaster Avenue line) is one of the five T routes of the SEPTA Metro that connect 13th Street station in Center City Philadelphia, Pennsylvania, to the 63rd Street–Malvern Avenue station in the Overbrook section of West Philadelphia. Service is operated by the Southeastern Pennsylvania Transportation Authority.

Starting from its eastern terminus at 13th Street, the T1 runs in a subway tunnel under Market Street. It has underground station stops at 15th Street, 19th Street, 22nd Street, 30th Street, and 33rd Street. From 15th to 30th Streets, it runs on the outer tracks of the Market Street subway tunnel used by SEPTA's Market–Frankford Line. Passengers may transfer free of charge to the Market–Frankford Line at 13th Street, 15th Street, and 30th Street and to the Broad Street Line at 15th Street. Connections to the SEPTA Regional Rail can be made at either 15th Street Station or 30th Street Station . There is an underground passageway that connects the ex-Pennsylvania Railroad's 30th Street Station to the Market–Frankford Line's 30th Street subway station, but this has long been sealed off due to high crime. An underground passageway continues to serve between the 13th and 15th Streets stations and Jefferson Station and Suburban Station, respectively.

The T1 exits the subway at the 36th Street Portal, whereas the other T branches surface at the 40th Street Portal. The T1 then runs north on 36th Street, passing the University City Science Center as it approaches Lancaster Avenue (US 30). At Lancaster Avenue there is a wye cutback, which at one point connected to the former Route 38 trolley to Lancaster Avenue when the T1 Line continued straight down Lancaster Avenue to Market Street, where it connected to a now-closed subway entrance at 23rd & Market Streets.

Continuing northwest on Lancaster Avenue, the T1 crosses over 40th Street, where there is a southbound track which diverts the T1 to 40th & Filbert Streets when the trolley subway tunnel is closed. At 41st Street there is a northbound track by which the T1 returns from 40th & Filbert Station. The tracks on 40th and 41st Streets continue north of Lancaster Avenue (part of the PTC Route 40 trolley line until September 9, 1956^[3]) to Girard Avenue and connect to the G trolley.

Continuing northwest along Lancaster Avenue to 48th Street, the T1 intersects Girard Avenue, where trolley G trackage joins that of the T1; as Girard is offset by Lancaster Avenue, the two routes briefly share tracks before Route 15 turns left to continue up Girard Avenue.

At 52nd Street the line reaches Lansdowne Avenue, where another cutback loop exists, installed in 1996 for emergency or schedule adjustments only. The T1 turns west on Lansdowne Avenue and at 60th Street, a pair of tracks on 60th formerly ended just short of the south side of Lansdowne Avenue. These tracks once belonged to SEPTA Route 46 when it was a trolley line (abandoned on August 11, 1957^[3]), and later served as pull-in/pull-out tracks for the then-Route 10 before it was moved to SEPTA's Elmwood Depot. When the then-Route 10 moved back to Callowhill Depot in the 2000s, trolleys pulled-in/pulled-out to Callowhill Depot via 63rd Street instead, using the outer end of Route 15 along with trackage which once belonged to the Route 41 trolley (abandoned on August 11, 1957,^[3] and now served by SEPTA Bus Route 31, another former subway–surface line until 1949). The 60th Street tracks were removed between Lancaster and Haverford Avenues in the early 2000s. The T1 turns north from Lansdowne onto 63rd Street, on which the line continues until it finally reaches the Malvern Loop, which has two (formerly three) tracks, sharing the off-street loop with SEPTA Bus Route 46.

The T1 was established sometime before 1887. On December 15, 1906, the line was integrated into the subway–surface trolley system by the Philadelphia Rapid Transit Company and was extended to 63rd & Malvern Streets.^[4] In 1929, it was rerouted so that it went on Landsowne and 61st rather than on Girard, replacing part of Route 44.

In 2020, two then-Route 10 trolleys collided in West Philadelphia, injuring 46.^[5]

In 2021, SEPTA proposed rebranding their rail transit service as "SEPTA Metro", in order to make the system easier to navigate. Under this proposal, the subway–surface lines will be rebranded as the "T" lines with a green color and numeric suffixes for each service and Route 10 was renamed "T1".^[6][7] SEPTA described that "most comments were positive" in the public comment period for this rebranding project.^[8]

SEPTA trolley modernization proposed new ALSTOM trolley vehicles, which will be delivered from 2027-2030, as well as extending the T1 to Overbrook station. This would make the T1 a more frequent route.

All are located in the City of Philadelphia.

Neighborhood	Station or stop	Connections	Notes
Market East	13th Street	SEPTA Metro: SEPTA City Bus: 27, 31, 32	Closed between 12:30–5:00am
Penn Center	15th Street/City Hall	SEPTA Regional Rail: all lines (at Suburban) SEPTA Metro: SEPTA City Bus: 4, 16, 17, 27, 31, 32, 33, 38, 44, 48 SEPTA Suburban Bus: 124, 125	Late night terminus
	19th Street	SEPTA Metro: SEPTA City Bus: 17, 31, 38, 44, 48, 62, 78 SEPTA Suburban Bus: 124
Center City West	22nd Street	SEPTA Metro: SEPTA City Bus: 7, 31, 44, 62 SEPTA Suburban Bus: 124, 125	Replaced 24th Street station
University City	Drexel Station at 30th Street	Amtrak (at 30th Street) NJ Transit: ACL Atlantic City Line (at 30th Street) SEPTA Regional Rail: all lines (at 30th Street) SEPTA Metro: SEPTA City Bus: 31, 49, LUCY	No direct passage to 30th Street Station
	33rd Street	SEPTA Metro: SEPTA City Bus: 30, 31, 49, LUCY	Serves Drexel University
	36th Street Portal
	36th & Market	SEPTA City Bus: LUCY
Powelton Village	36th & Lancaster
	Powelton & Lancaster (WB)
	38th & Lancaster
	Saunders & Lancaster
	Spring Garden & Lancaster
	40th & Lancaster	SEPTA City Bus: 30, 40, 43
Belmont	Wallace & Lancaster	SEPTA City Bus: 43
	41st & Lancaster	SEPTA City Bus: 31, 40, 43
	42nd & Lancaster	SEPTA City Bus: 43
	Parrish & Lancaster
	Ogden & Lancaster (WB) 44th & Lancaster (EB)	SEPTA City Bus: 43
Mill Creek	Westminster & Lancaster (WB) 45th & Lancaster (EB)	SEPTA City Bus: 64
	Wyalusing & Lancaster
	47th & Lancaster
	48th & Lancaster
	Girard & Lancaster	SEPTA Metro:
Carroll Park	49th & Lancaster
	50th & Lancaster
	Media & Lancaster (EB)
	52nd & Lancaster (WB) Lancaster & Lansdowne (EB)	SEPTA City Bus: 52
Overbrook	54th & Lansdowne
	55th & Lansdowne
	56th & Lansdowne
	57th & Lansdowne	SEPTA City Bus: G
	58th & Lansdowne
	59th & Lansdowne
	60th & Lansdowne	SEPTA City Bus: 46
	61st & Lansdowne
	62nd & Lansdowne
	63rd & Lansdowne	SEPTA City Bus: 31
	Jefferson & 63rd
	Columbia & 63rd (WB) Lebanon & 63rd (EB)	SEPTA City Bus: 46
	63rd–Malvern/Overbrook	SEPTA City Bus: 46, 65, G SEPTA Suburban Bus: 105	Five blocks to Overbrook Regional Rail station

• Official SEPTA Route 10 schedule and map