On my club's layout, which was originally DC only, they used the old 3 auto bulb method, which "browns out" the power to the rails. Since incorporating DCC as an alternative power and control, they have retained that system. It means that it doesn't shut off the power totally, only lowers the voltage to the tracks. I have remonstrated (suggested really) with the club electrician about the risk to the DCC system (much more expensive to replace, let alone everybodies decoders of the bulb arrangement. The irony is, as I mentioned, with the NCE system we use, it works in a virtually identical fashion, but with better system/decoder protection. I had the experience last week (not the first time) of someone else having a derailment/short that flickered the bulbs and jerked my multi consisted engines. The result being that they got thrown into a phantom or garbled consist from which every decoder has to have it's consisting CV19 reset to 0. Unfortunately, this didn't work this time, as there were 4 locos involved and I had to wait till I got home and could use my base station to achieve it. Took 2 attempts with 2 of the engines to get them back. The price of club membership.
That system did cause some damage to two MTH 60' flat cars also some time ago. They have all metal trucks (sprung bolsters), metal wheels (1 end only insulated) and metal axles. Some (many) of the axle's insulators have been fitted to opposite sides, resulting in a direct short, through the trucks, diagonally, which, even though all 3 bulbs were brightly lit, were heating up. All wheels were on the tracks, so it wasn't till I picked one car up and put my finger on a truck that was hot (burning) that I realised what was happening. Damage was fortunately minor, just some slight melting of the plastic around the truck pivot, but as they too are metal and joined together through the base of the car, could have destroyed it, if left too long.
So, my message is. If using DCC on your layout, rely on the systems inbuilt circuit breaker, or it it's big enough to need power districts and additional boosters, maybe look at additional ones. Don't use bulbs.