I tested every section of track (I had to make two separate track loops to include all of the pieces). There's a moderate power drop when going across the switch track sections. The connectors probably need to be cleaned.
There are a few little spots of tarnish on the tracks; nothing that affects function, and some metal polish would take it right off. The pieces have acquired some of the usual dust and grime that comes with playing with legos, so be aware that they could use a wash. Everything is otherwise in good condition.
The speed controller transitions smoothly from stop to full speed in both directions, the wire insulation is intact, and the tracks snap together firmly. Feel free to contact me if you have any questions. The item "Lego 9V Electric Train with Motor, Track, Speed Control, and 4539 Partial Set" is in sale since Wednesday, January 6, 2021. This item is in the category "Toys & Hobbies\Building Toys\LEGO Building Toys\LEGO Complete Sets & Packs".The seller is "ononys" and is located in Everett, Washington. This item can be shipped to United States.