Lost count about twenty years ago, and have added since! Most of my diesels are Athearn Blue Box Super Power (with the flywheels), ?? F7's and 3 SW1500's, 4 GP7's, 1 SD7. All those in DC.
I have recently acquired 3 Proto2000 E6's (1 turned into a Burlington E5) with DCC and sound, and 3 P2k E7's, 1 P2k F7A/B and 1 Intermountain FP7A/F7B w/DCC & sound; and an Intermountain FTA/B also w/sound & DCC. Lot of problems with the P2k wheels and axles, however.
In steam, I have 3 MDC 0-6-0's which I bought as kits when I was a teen, and modified into a couple of 2-6-0's and a 2-6-2. The majority of my steam, however, is Mantua/Tyco 2-8-2's and 4-6-2's. I only have a couple of each in their original configuration. All but two have been re-motored, and all have had gearboxes installed for lower-speed operations. Four Mantua/Tyco 2-8-2's were used to create a pair of
2-10-2's, and a pair of 2-10-4's. Those have Canon coreless motors (no longer made
), and are extensively detailed. A pair of Pacifics were kitbashed to a 4-8-4, and another Pacific was converted into a Burlington S-4, 4-6-4 #4001 (Big Alice the Goon without the steel shrouding, but with the vestibule cab.) All the stretched models will run around 18" radius curves, by virtue of blind center drivers that are shimmed up .010" off the top of the rails.
I haven't tried any of the new Mantua locos, but I bet they run well with the newer can motors and gear boxes. Cheap they ain't anymore, however!