It was created in 1830-1834 by constructing the Westerdoksdam and Westerdoksluis, forming a reliable deep port closed off from the tidal IJ.

The Westerdoksdam was a 2,010 m long dyke constructed through the IJ from the west bank of the Haarlemmersluis in the Martelaarsgracht to the Spaarndammerdijk.

[2] By July 1834 the dyke was almost finished, an openinghad been left to allow shipping till the Westerdok Lock was completed.

It meant that inside the area closed off by the Westerdok Lock, the water level remained more or less constant.

A special feature of the Westerdok was Drydock II of the Rederij der Drijvende Droogdokken, a company that provided service by floating dry docks.

Instead of protecting a safe harbor, the Westerdok Lock became an impediment to ships that wanted to unload in Amsterdam.

When the North Sea Canal was constructed, this dyke got some piers at which large ships could attach directly, instead of transloading to barges.

[7] For the Westerdok, the railway plan was not so problematic as for the Oosterdok, because the main line lay south of the dock.

The railways then decided to expand the central station, and to create Westerdokseiland, upon which a new classification yard would be constructed.