There was a large number of Orion VIs at Four Mile who have now moved to Landover Division. How did they get there? Was there a massive bus convoy from Four Mile to Landover in the dark of night?
Looks like you're behind in time.
About 1.5 years ago, when the last of the Orion VII moved into Four Mile Run, all the older buses (ALL of them - Orion VIs, Flxible Metros, Orion Vs, etc) moved to other divisions. This resulted in not only different buses appearing which came from FMR, but other buses from other divisions to move as well.
Let me focus on FMR for now. Before this giant move, FMR consisted of Orion VIs 2000-2032, 2063-2084*. 2088, 2098, and 2099. Orion Vs 4200-4246, 4287-4299*. Flxible Metro-Ds 9746-9765 and 9816-9835. Plus more Flxible Metro-Bs that are either retired or gone somewhere else.
In the case of the Orion VIs going to Landover, here's what happened. Landover already had Orion VIs, they were 2033-2062, 2085-2087, and 2089-2097. So what happened was that 2000-2032 moved to Landover, which displaced the other Orion VIs to Western and Montgomery. 2033-2062 going to Western (as well as 2063-2066), and 2085-2087 and 2089-2097 going to Montgomery (as well as 2067-2084 and 2088).
EDIT - * means that I'm not 100% sure if this is correct, but I'm making a guess based on my observations.
What are the asterisks for?
Yes but how did they get there? Was there a giant bus convey across the river?
Well the garage has a capacity of # vehicles and the Orion VIIs might have arrived 5 at a time, so it didn't take forever and a day.
I'm not sure if they were accepted at CET or at Four Mile; if the former, they probably would have taken a few Landover Extra Board drivers to Four Mile as they delivered the VIIs and had them drive 5 VIs back with them. If they were accepted at Four Mile, they'd probably send 6 buses out - five to drop off, one to bring the drivers back.
A third option might have been to have a Four Mile bus and driver stay at Landover at the tail end of rush hour and have any VI drivers deadhead to Landover instead of to FMR, then use that one driver/bus to shuttle them all back...this would work if they didn't have too many people on Extra Board but would cost some overtime.
But, there's no high tech or advanced or complicated way to do it - at times, you probably did have a good line of buses going over all at once.