I think one reason that diecast rolling stock is not wildly popular is the weight impacts how many cars you can pull, especially if you have grades.
You might be surprised. A large articulated steamer can haul a lot of cars, probably at least 20-25 diecast cars. My Vision Line Big Boy pulled 70 cars around the layout at Harry's place without breaking a sweat, and that includes several grades. I'm pulled a dozen diecast cars with my upgraded Phantom locomotive.I have a couple trains of Erie and B&O in these models. I am figuring around ten would be the limit for a large steamer or multiple diesels. Mixed with some MTH plastic cars, I hope to run a train of about 20 cars…