What's "Chug" in Estonian?

MOP 9000s, C36-7s, in Cajon Pass

When the photo above was taken in the 80's, Estonia was still under the Soviet thumb. The majority of  the road power of Eesti Raudtee is former U.S. GEs. (link.)  I can't find out if there is an onomatopoetic word such as chug in Estonian, but you would think there is one.

Estonia YouTube playlist:

Estonian C36-7 Chase - Yes, He Rolls the Window Down

MOP 9000s

A solid set of Missouri Pacific 9000s, C36-7s, drift downgrade by the Mormon Rocks, Cajon, California

WB at Rana, California

A railfan favorite the, C36-7s on UP, back when the Borg was maintaining the pretense of a separate identify for the MOP. These units now toil in Estonia.