You arrive at train station Aachen West, and follow left by the tunnel. Turn right onto the "Geschwister-Scholl-Straße" and go straight down all the way to "Templergraben". On the way you will pass the "Schinkelstraße". On the left site you will see the main building of the RWTH Aachen University.
Until Aachener Kreuz take A4 direction Heerlen/NL and leave the highway at exit Aachen-Laurensberg/Uniklinik/TH. After the exit turn right towards Aachen. Follow this street (L232) to the city gate "Ponttor". At the crossing turn right onto the street "Pontwall". At the next traffic light turn left onto "Wüllnerstraße" and at the next traffic light turn right onto "Templergraben". After 50m you will see the main building of the RWTH Aachen University on the right.
Line 13 until bus stop Technische Hochschule, main building of the RWTH Aachen University, 2nd floor.