LEGO 139 Electronic Control Unit Forward, Backward and Stop is a vintage Trains set from 1969 valued at $1,155 for new and sealed sets, up 9230% from an original retail price of $12.38. Annual appreciation has averaged 11.82% since release. Used copies are valued between $726 and $1,409 depending on condition.
LEGO 139-1 Electronic Control Unit Forward, Backward and Stop is a Trains/4.5V supplementary set released in 1969, containing 13 pieces. It includes an electronic train whistle with adjustable functions, a whistle control block with forward, stop, and reverse settings, a microphone, and two 14-stud wires with blue and red connectors. The accessory pack was used with the 118 Electronic Train and 138 Electronic Train sets. It was also known as Electronic Control Unit (Forward/Backward - Stop), and unlike set 139A, this version included reverse operation.
A new and sealed Electronic Control Unit Forward, Backward and Stop is currently valued at around $1,155, with annual growth of about 11.8% that is expected to level off to around 8.9% in the coming year, making it a solid investment. The average used price is $959 for those in good overall condition. Based on current trends, this set could be valued near $1,249 within the next year. New and sealed listings currently range from $1,068 to $1,112.