What would be really cool to see is a video of 2 O Gauge T-1's double headed pulling all 6 lionel cars plus a set of 8 SGL passenger cars like a Ramble!
I'm sure once COVID is over, a close friend and I will be getting together with each of our 6 pack of Lionel ones to put behind his T-1. We may even try it with my G-3, though I may just make that 8 cars.
I don't think any of the cars have markers. There are companies that sell them and drumheads though. I am thinking about adding them eventually.