Preserved locomotives fitted with the mandatory electronic equipment are allowed to operate on the national mainline. Currently there are five Class 50s so equipped.
Since returning to the mainline these have all seen use on many railtours and land cruises for a variety of train operators. Destinations for these tours have been varied. The locomotives have revisited their old stamping grounds as well as places never frequented by the three classes such as Wick and Thurso in the far north of Scotland.