The Class 81 is the first and oldest type of electric multiple unit introduced by Keretapi Tanah Melayu for its KTM Komuter service. 18 sets were designed by Hunslet TPL and built by Jenbacher Transport and were delivered in stages. The class 81 currently operates in a fixed 3-car formation for its regular service. During the 1995-1999 period it used to operate at peak hours in a 3+3 car formation. But this configuration was soon discontinued.