These train cars are fitted with greenish-blue Glastroch (Germany) windows glass, and are almost the same as the first generation train cars before their upgrades, except that a louder, lower-pitched noise can be heard when the train speeds up or slows down. The run number display on the front of each train is made up of electronic green flip-dot display, as opposed to the manual plastic rollers of the C151 trains, while the rubber strips between the doors are thicker. The trains have a full white body and a thick red stripe in the middle. Similar to the C151 trains, the Siemens C651 trains had no visual passenger information systems, but only a built-in audio announcement system, until STARiS was installed and activated around 2010.