Its no surprise that the popular Swish brand has a number of products on this page of discontinued parts. A corded version of most of the tracks which spanned decades of production were available until Sunflex took over the brand in 2008. So below you will find a number that haven’t been available for over a decade at the time of writing 2020.
The only corded track which remains available is the Superluxe, but spare parts aren’t the list and photos are below. My recommendation would be that if you have one of these old corded Swish tracks, then it’s probably about time that you changed it as the other plastic parts will have also become brittle with heat and sunlight over the years.
Anyway the photos below should help you identify what you have
As I say most of the old Swish tracks had corded version:
Superluxe tracks included a double centre return pulley on longer lengths. Interestingly it is still available though it is offered as part of the Rolls Superglide Centre Pulley set, which from around 2010 also included the centre joiner; the original sturdier Rolls Superglide Centre Pulley being discontinued. Both pictured below, along with the Superluxe Down Pulleys