This post motivated me to try something similar. I previously discovered (by accident) that it was possible to couple two trains together. I was driving a 101 DMU on Tees Valley and overshot the platform at Eaglescliffe... I reversed back and found the following (freight) service had arrived in the platform! I've since extended the thought process and utilised Scenario Planner to emulate a railtour on East Coastway. What I did was start an AI service formed of a Class 33 and WSR stock from Eastbourne. Starting at the same time I spawned in a pair of Class 20's Light Engine at Hampden Park. I drew the the Class 20's past the signal at the end of the platform. About 3 minutes later the 33 approached Hampden Park and stopped at the red aspect. I reversed the 20's back onto the 33 and coupled up. The next signal indicator showed a red aspect at about 8yds, but when I started to move the consist forward the next signal indicator changed to green 600+ yds. All clear then for a run to Brighton;-))