Haydarpaşa suburban

Haydarpaşa suburban
Haydarpaşa suburban
	25 kV AC
Operating speed	40 km/h (25 mph) average
Route map
	Legend
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The Haydarpaşa suburban (

Haydarpaşa Terminal in Kadıköy to Gebze

. Since its opening in 1951, it was the busiest commuter rail line and busiest TCDD service in Turkey, until it was discontinued in 2013.

Electrified in 1969, the line was the second electrified commuter rail service in Turkey, after the

Bosphorus

.

The route traversed the southern shore of Istanbul's Asian side, passing through important districts: Kadıköy, Maltepe, Kartal, Pendik and Tuzla. The line then crosses into the Kocaeli Province into Gebze, where it terminates. The State Railways has operated its regional service to Adapazarı and mainline service to Ankara on the line as well, making it one of the busiest rail lines in Turkey, in terms of passengers and number of trains.

History

A railway to Gebze was originally built by the

Republic of Turkey was formed in 1923, the CFOA continued to operate commuter service until 1927, when the Turkish State Railways

acquired the CFOA. The newly formed State Railways (TCDD) continued the commuter service formerly provided by the CFOA.

After

E40000 electric locomotives started to operate on the line. In 1972, E14000 EMUs were introduced, and the E40000 were put on regional service between Istanbul and Adapazarı

. The route however deteriorated for the next three decades and during the mid-2000s, the EMUs were in bad shape and the tracks were in need of repair.

In 2003, the

Bosphorus, as well as the upgrade to this line. Plans were finalized, and the line was first partially closed between Gebze and Pendik, with the whole line closed as of 19 June 2013 for at least 2 years. The planned reopening in June 2015 was delayed until March 2019 when the line went back into service despite protests from the unions that final tests had not yet been completed.^[4]