As has been mentioned the two doors in the front open up to link trains. This is illustrated in this pic. This train will be split up halfway, one half going to Den Haag (the Hague) and the other ... (more)
The "koploper" (frontrunner) trains are used for longer distance in the Netherlands. The driver sits in an elevated position. This makes it possible to link several trainsets together. Up to 3 set... (more)
This is the most commonly used train for intercity trains. More of them are ordered to replace the few "Serie V" trains (see pic 27084) that are still running intercity services.