Pt31 was based on too heavy and too long Pu29 and occured very well for Polish routes, so the production fruited in almost 100. This Pt31-64 is at Museum-Depot Chabowka (picture taken on July 21, 1997).

Photo and scan: Jerry D. Stawarz 
 e-mail: jareks@fs-samba.com.pl
 http://panda.bg.univ.gda.pl/~jareks/pekape