Post 12 7-16-2016 (revised 11-24-2023)
Casco, yes the tower on the TT is to provide electric power to the motors on the TT that rotate the TT. Charlie
Medium Weight (Lionel 2018, 2026) Steam and Diesel Engine Upgrades 1986-2000s
Background: Engines from layout start in 1977 were light weight plastic bodied Lionel 2-4-2’s, and a Marx 999 and 666. These engines weigh 2.5 to 3.5 pounds and do not have Magna-Traction and were bought mostly from 1986 to 2000. They run very well on O27 tracks and Marx 1590 metal frog switches. They are limited to pulling 4 or 5 light weight cars.
Plastic shell Lionel 249, 2-4-2 with 2 way E unit Good runner on 027 track and Marx switches 
Marx 666 2-4-2
Medium Weight Steam Engine Upgrade
An upgrade to medium weight cast medal body Lionel 2016, 2018 from 1955-6 and 2026 from 1951-3, all 2-6-4 or 2-6-2, and other Engine upgrades started in 1986. A Lionel 2018 was purchased in 1986 and later a 2016 and several 2026 2-6-4 engines. They all are similar with the same motor and body shell. They weight about 3.5 pounds and have 6 drive wheels for more wheel to track adhesion verses 4 drive wheels for 2-4-2 engines and do not have Magna-traction. They pull better than the plastic shell 2-4-2 and handle the 027 curves and switches very well. They will pull six or so cars, some being heavier operating cars. Their front marker lights are cast in the loco body but seem robust as none of my several locos have broken marker lights.
The run very well and are my favorite for running two pairs of them, when I run two loops with 2 trains per l loop with the relayed system. They are easy to find and fairly inexpensive and I have 9 of them now.
Lionel 2016, 2-6-4 cast metal shell, 3 way E unit, medium weight engine 
A picture of 2-6-4 Lionel 2018. This engine is my first 2-6-4 and I probably paid too much. I really loved the way it ran and pulled. Added a Rock Island decal in effort to differentiate from other Black engines.
Lionel 2026 similar to 2016 and 2018, with the same shell and motor and seams easier to find. The 2026 is better equipped with smoke and some have extra valve gear making them more attractive.
The 2026 below was made earlier in 1953 and is a 2-6-2 with more features like hand rail, twin valve gear, cast rear truck and smoke that may make rings and slide power pickups
I also picked up a Lionel Alco AA 219 diesel set and repainted a Lionel caboose MP blue to match. I added a headlight to the dummy A unit and lighted marker numbers to both.
Diesels Added
Lionel Caboose repainted to MP colors to match Lionel 219 MP AA diesels
Two sets of Marx 1095 F3 Santa Fe diesels were added and one set was repainted as the grey plastic and red paint is not very well done (this set was ABA). I was fortunate to pick up some O gauge Santa Fe decals at a train show.
Painted and decaled Marx 1095 F3 Santa Fe 
Marx 1095 with original red and yellow paint and grey plastic passing for silver
I also procured two tin plate Marx 3152 Santa Fe passenger cars and a tin plate Marx 3197 Santa Fe observation car which I added lights to the marker dummy lights. The Lionel 2400 series passenger cars were too rich for me then. They would come later. Many of these cars came from local train shows in Little Rock and from my contact Dave on trips to visit my parents in Pittsburgh.
Marx 3197 Santa Fe passenger car with working marker lights added 
One of Two Marx 3152 Santa Fe passenger cars
I also got a low cost and quality Lionel 9303 log dumping car and a Lionel 9304 coal dumping car that dump via uncoupling tracks into plastic trays. I would get heavy into operating cars later.
Charlie
