Complex sentence: The rolling stock of the Capital Line is composed of trains of either Siemens-Duewag U2 or Siemens SD-160 cars.Tthe Metro Line uses only SD-160s, as the older U2s are not compatible with the Metro Line's newer signalling system.
Split into simpler sentences: The rolling stock of the Capital Line is composed of trains of either Siemens-Duewag U2 or Siemens SD-160 cars. The Metro Line uses only SD-160s, as the older U2s are not compatible with the Metro Line's newer signalling system.