Six speed test scenarios for the 6 LNER A4 varients over a stretch of the London to Brighton line are available in the A4 Pacifics pack - https://store.dovetailgames.com/uk/product/260989/class-a4-pacifics-loco-add-on I was surprised that no results are listed in the forum, perhaps they're lost deep on the Facebook page, since it was released in 2013. I guess the locos can be swapped out so it can be run with any type of loco. Any idea what the physical maximum track speeds are over the points and around the corners ? What times have people got with the different scenarios/weather ?
If it is a Career Scenario you will not be able to swap locos As a Standard Scenario you could use any loco but then you would not get any points Peter