Using a light bulb will not prevent current from flowing through a short, but instead will only provide a load so your DCC booster's internal overload protection will not work to shut down the booster.
The commonly-used 1156 bulb draws about 2.1 amps at 12v, which comes out to about 25 watts. So that's how much current will be flowing through (for example) that shorted loco truck. That's more than enough to melt the truck sideframe (think in terms of the heat produced by a 25-watt soldering iron).
My advice is to use skip the bulb and use a proper DCC circuit breaker.
The old trick of using 12v auto light bulbs will work to help protect the circuit. Remember, this is an old trick and DCC has advanced to a state where this type of protection may not be vialble to protect all the components.
The bulb will DECREASE the total volts/amps going to the DCC decoder if there is a short. The bulb WILL NOT completely shut the power off from reaching the decoder and damage could still happen. There are many older books on wiring the bulb to help protect the circuit. Check You Tube.......https://www.youtube.com/watch?v=IzrfarW3geQ
The currently available circuit breakers are becoming cheaper with greater options. Circuit breakers completely shut off the volts/amps from reaching the decoder and other DCC components; no power = no damage!
If budget is a concern, you could buy 1 circuit breaker to protect your electrical components and add more as the budget allows.
As a side note....With my current DCC sytem (CVP Easy DCC and PSX breakers), I am using a combination of breakers and bulbs. There are reasons for this set up but it has worked flawlessly.
LION has such a lamp. Him uses DC and not DCC. It works well enough on DC with one train, but LION runs 10 trains on the layout of him, and that draws enough currants to light the lamp even with no shorts.
LION has FIVE power supplies on the layout of him. Him has an automotive fuse block with five fuses in it to protect the supplies of him.
If him has problem, him can patch in the lamp to see that the circuit is shorted, and then him can dosconnect things until the lamp goes off, and then him has found his shorts. It saves blowing fuses while testing things.
Will it work on DCC, LION knows knot.
ROAR
The Route of the Broadway Lion The Largest Subway Layout in North Dakota.
Here there be cats. LIONS with CAMERAS
As Shutlz said, "I know nothing!" about this, but a google search "site: cs.trains (xyz)" found these 2 older items. (You can paste these into your browser; i.e., I can't remember how to make these forum links clickable.)
http://cs.trains.com/mrr/f/744/t/215408.aspx
http://cs.trains.com/mrr/f/744/t/127623.aspx
Is the driver budget? If so, the OG-CBs were all I needed for my simple main line, at $25. I liked them because they are electronic, without relays. I needed 2 OG-ARs ($32) for my reversing loops. There may be cases where fancier adjustable or other features are adviseable but for my NCE Powerhouse Pro and simple layout the advice from a Tony's guy was the simple models would work for me. Nearly 5 years now with no issues.
https://tonystrains.com/product/dcc-onguard-og-cb/
https://tonystrains.com/product/onguard-og-ar/
Paul
Modeling HO with a transition era UP bent
I am beginning a new HO layout and will be using DCC for the first time. I remember reading an article some time ago about using 12v bulbs in place of the more expensive circuit breakers for the power districts. Does anyone have any experience with using bulbs for this purpose?