Monorail is a subtheme of Service Packs introduced in 1989 and currently consists of 3 sets. All sets were released in 1989. As of today, the average annual growth of sets in Service Packs Monorail is approximately 5.7% per year.
Most valuable Service Packs Monorail set
5040 Monorail Motor 9 V $199.39
Highest growth Service Packs Monorail set
5039 Monorail Stop / Reverse Switch +874.29%
The Monorail service packs of 1989 were spare parts for the LEGO monorail system used with the Space sets. 5039 Monorail Stop / Reverse Switch is a light gray track switch that makes a train stop or change direction. 5040 Monorail Motor 9 V is the white 9V motor sold separately, and 5041 Space Track Connector Lead 9V 10 cm is a short black wire with 2 x 2 brick ends for carrying power to motors and switches.
3 sets

5039 Monorail Stop / Reverse Switch

Theme / Subtheme Service Packs / Monorail
Year 1989
Pieces 3
Availability Retired
5039 LEGO Monorail Stop / Reverse Switch
Retail $5.99
Value $58.36
Growth  +874.3%
Annual growth 6.0%

5040 Monorail Motor 9 V

Theme / Subtheme Service Packs / Monorail
Year 1989
Pieces 1
Availability Retired
5040 LEGO Monorail Motor 9 V
Retail $29.99
Value $199.39
Growth  +564.9%
Annual growth 5.4%

5041 Space Track Connector Lead 9V 10 cm

Theme / Subtheme Service Packs / Monorail
Year 1989
Pieces 1
Availability Retired
5041 LEGO Monorail Space Track Connector Lead 9V 10 cm
Retail $3.99
Value $35.06
Growth  +778.7%
Annual growth 7.0%