Nice, I have read on here about the heat shield thing, is that for all the sets? I have added passengers on my R42 and R12 and didn't notice anything on the roofs. What type of tape you use? like the tape for A/C duct work?
You want to use silver metallic reflective tape (much sturdier and highly reflective compared to ac duct tape). The early subway models lacked any protection for the top of the engine shell and were prone to heat damage from the flimsy lights installed at the top of the casing that houses the electronics, particularly when they become unseated and move upwards from handling the engine car. Placing the metallic tape on the inside top of the shell, particularly over where the lights are seated eliminated this problem, which usually first revealed itself by the appearance of a “bubble” on the exterior of the shell right where one of those lights is located. Later models started including a heat shield, but I always inspected to make sure it was there, since some forum members reported that certain newer models still lacked it. Even when I see them properly placed, I stuck a piece of metallic tape over the part of the interior roof where the lights are seated for extra protection. Keep in mind, you only need to do this for the engine cars, as the lights in the passenger cars are better seated and not prone to moving and causing the heat damage to the roof. In fact, I own a considerable fleet of subways and have never had a problem with a passenger car.
The subway engines pack a lot of electronics and lights in a small space, causing them to run very hot. This also places a major strain on the engine electronics, adding to board failures. In order to extend the life of the engine, you should try and run them at the lowest voltage you can. I run mine at around 15-16 volts when just doing continuous operation. I use around 17 volts (sometimes 18 depending on how many passenger cars) when running in auto mode with station stops. This is because the engine needs more voltage to gain momentum after a station stop. I try and avoid using the two car add ons when running in auto mode, only running the original 4 car sets, which places less strain on the engine from the continuous stopping and starting when in auto mode, helping to further minimize engine heat. Other tricks include glueing some of the windows back on in a half open fashion or leaving them off, so air can flow into the engine, cooling it when running. This can be done for models like your r-12, with the flimsy windows that are prone to becoming unglued and falling off over time. Other models have the better, sturdier windows and don’t allow for this. Other things to do is to keep the engine well oiled and lubed, as well as regular oiling of the passenger cars to minimize drag and strain on the engine, which also helps decrease engine heat.