639 - Üçüncü köprü - ICARailway Infrastructure

Gebze Halkali high speed line project

Europe and Asia will be connected by rail for the second time after Marmaray with this project.

Enriched on 13.02.2021 with up-to-date information

Two continents are planned to connect by rail via the new bridge on Bosphorus. This will be an alternative to Marmaray, connecting Gebze to Sabiha Gokcen and Istanbul airports in two sides of Istanbul. The line will end at Halkali.

With a change in plans, the 124-km-long Gebze-Sabiha Gokcen Airport-Istanbul Airport-Halkali project is updated as 213 km long project reaching to Adapazari in east. The cost of project is tripled with this change.

Adapazari-Sabiha Gokcen Airport-Istanbul Airport-Halkalı high speed line

Gebze to Halkali in 60 minutes

With this project, the travel time between Adapazari and Halkali will drop from 2:40 hrs to 1:30 hrs and between Gebze and Halkali from 2 hours to 1 hour. Access to Istanbul Airport from Asian side will be much easier. The transfers between two airports will be very easy and fast.

When line is completed, the HSTs heading to Halkali will use this line. There’ll be train service between two airports.

Adapazari-Sabiha Gokcen Airport-Istanbul Airport-Halkalı high speed line route

Project needs external fund

The preliminary analysis was completed for the line. It’s expected to cost 36 billion TL (€ 4.3 bn). 30 bn of that is expected to be funded by external credits. Engineering works have not started yet (as of 2021).

Freight trains can use the line

This line will be constructed as “high standard line”, not “high speed line”, which means freight trains can use the line.

Freight trains can only pass through Marmaray during night, so there’s limited capacity for them. Dangerous goods are not allowed to tunnel. This project may overcome some of these restrictions.

This line will have a connection to Halkali-Kapikule high speed line at Catalca. Thus, trains coming from Asian side may lead directly towards Europe directly.

Strong metro connections

There will be several metro connections to this line. Marmaray, Halkali-Kirazli metro and Istanbul Airport metro at Halkali, Kadikoy metro at Sabiha Gokcen Airport, Darica metro at Gebze.

Cover photo: ICA ©

12 replies »

  1. Looks like a beaut of a bridge, not to mention a beaut of a high-speed line! If freight trains don’t use the bridge, will they use the tunnel under the Straits?

  2. Phil,
    The Marmaray project is many years behind schedule, and the specification has been changed several times. The lines which ran into central Istanbul on both Asian and European sides were both completely worn out, so the tracks have been lifted and all the signalling and power equipment removed, in anticipation of a total rebuild. The central section – including the tunnel under the Bosphorus – has been open for a few years. However there are still significant gaps on both sides, where total rebuilding of the railway hasn’t even started yet. All that is left is a muddy path where the railway used to be. You can expect to wait for another couple of years before through trains start running, I would guess.

    • Thanks, Jeff, for your detailed response. That Europe and Asia may some day be able to interchange freight traffic is exciting. Let’s hope that some day comes soon!

      I also look forward to Europe being linked to China and the intermediate countries via a standard-gauge line. Such interchangeability has been a given in North America for over 100 years, as it has been in all of Europe, except Spain, I think.

      By the way, may I ask you a favor? I’m a professional writer/editor with 16 years’ experience, most recently as editor of Investor’s Digest of Canada based in Toronto.

      But I’m now hoping to start writing — for pay, of course!– about railways and airports. So, do you know of any railways, railway industry organizations, or construction companies that build railways that might be looking for an English language writer/editor? With such companies, I’m confident I could add value.


      Phil Fine
      Jerusalem, Israel

  3. Phil,
    I’ll keep my ear to the ground for you,but nothing immediately springs to mind.

    • Thanks, Jeff. I appreciate it. Keep the observations coming!

  4. I have got one question: As of now I thought when Marmaray is complete, the YHT and hopefully some mainline trains are going to start from / terminate at Haydarpaşa.
    Now this article suggests that a few years after the completion of Marmaray, YHT trains to Ankara and Konya are going to cross the bridge, which is incompatible to connecting Haydarpaşa. Does that mean, Haydarpaşa is going to revived just for a few years and then closed down again (at least for YHT), having the trains terminate at Halkalı?

    • Good question. I just can say what I guess. Some of the trains will depart from Halkali, and some others from Haydarpasa. I’m quite sure there’ll be enough passengers from both sides. And note that Haydarpasa is a much better point for accessing city center of Istanbul.


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