Air production on the locomotive was granted by two C38 type compressors; later they were upgraded with the more reliable W242, however, on some units, only one compressor was replaced, leaving one of each type in use on a single locomotive; the C38 produced air until 8 bars in main reservoir tanks were reached, while the W242 from 8 to 9 bars. In fact, on these units, only the W242 was used on normal conditions; the other one only if pressure dropped below 7 bars.