T4 (Istanbul Tram)
T4 Topkapı - Mescid-i Selam tram line is a light rail line in Istanbul, Turkey, operated by Istanbul Ulaşım AŞ. It runs from Topkapı north to Mescid-i Selam, a total of. The T4 line operates its own right-of-way in a street median for most of its route, though with a few at-grade crossings, thus technically making it light rail though the operator Metro Istanbul categorizes it as a tramline.
The first section of the T4 line opened between Edirnekapı and Mescid-i Selam on 12 September 2007. An extension southwest of Edirnekapı to Topkapı was opened on 18 March 2009.
Connections to the M1 line are available at Vatan station, while connections to the T1 tram line and the Istanbul Metrobus are available at Topkapı station.
Rolling stock
ABB
For a brief period of time, bulky high-floor ABB LRVs were used. After additional rolling stock was added however these trains were moved to operate on the M1 line.
Duewag
These are old B80S and B100S sets that were used on Cologne Stadtbahn and purchased in 2007. They were used on both T1 and T4 lines and with the arrival of Alstom Citadis trams on the T1 line they began to operate on the T4 line only.
From 2008, 63 units. Same vehicles used in on the Adana Metro and very similar to the LRTA 1100 class in Manila, Philippines. Unlike the other models, these only have a cab at one end.
RTE
More recently new high-floor trams that were constructed by Metro Istanbul itself are also used. During its development, there were intermediate models that operated on the line.