In 2006, LEGO released 4 City Trains sets, all of these sets have been retired. For that year, the total price of all retail sets cost $272, today those sets are valued around $740, a growth of 172%.
Most valuable 2006 LEGO City Trains set
7898 Cargo Train Deluxe $392.53
Highest growth 2006 City Trains set
7897 Passenger Train +233.37%
Most owned 2006 City Trains set
7895 Switching Tracks
4 sets

7895 Switching Tracks

Theme / Subtheme City / Trains
Year 2006
Pieces 8
Availability Retired
7895 LEGO City Switching Tracks
Retail $15.99
Value $17.90
Growth  +11.9%
Annual growth 2.9%

7896 Straight and Curved Rails

Theme / Subtheme City / Trains
Year 2006
Pieces 16
Availability Retired
7896 LEGO City Straight and Curved Rails
Retail $15.99
Value $30.00
Growth  +87.6%
Annual growth 6.2%

7897 Passenger Train

Theme / Subtheme City / Trains
Year 2006
Pieces / Minifigs 501 / 3
Availability Retired
7897 LEGO City Passenger Train
Retail $89.99
Value $300.00
Growth  +233.4%
Annual growth 8.1%

7898 Cargo Train Deluxe

Theme / Subtheme City / Trains
Year 2006
Pieces / Minifigs 856 / 5
Availability Retired
7898 LEGO City Cargo Train Deluxe
Retail $149.99
Value $392.53
Growth  +161.7%
Annual growth 3.2%