Subsidiary companies operated Citylink vehicles on express services originating from their operating area, and where long-distance services spanned one or two operating areas, the routes were shared between the companies. The level of involvement of the subsidiary firms in providing Citylink work varied with size and geography. Central Scottish, Strathtay Scottish, Kelvin Scottish and Clydeside Scottish were the smaller contributors as no major city or destination lay within their main operating regions. Indeed, Clydeside marketed its own express services within its area as "Clydeside Quicksliver" with its own distinct brand.