Q: Your recommendation is to have a DB150 booster at no more than 50 foot intervals. Will one booster handle all track in that 50 foot area, i.e. a passenger terminal throat with many turnouts and switches?
A: The "50 foot intervals" applies to the maximum distance which boosters can be located from each other.
This is a conservative recommendation. You should consider how much power will be consumed in a district when locating boosters around the layout.
If your power district is a single track railroad stretching over hundreds of feet of linear distance, boosters should be placed at 50 foot intervals or less to minimize the voltage loss over the length of the power bus.
In practice, there may be only one or two locomotives with a few passenger cars with lighting, thus very little actual power will be consumed in the power district.
In the case of a dense locomotive terminal adjacent to a busy passenger terminal, you may want to use mulitple boosters, each supplying power to a separate power district within the terminal area of the layout. In this situation, you might have dozens of locomotives, each consuming power even when they are sitting at idle (because the locomotive decoders will still be drawing power, even if the locomotives are not moving). Likewise, each lighted passenger car will be drawing power, too. The passenger car lighting can be more efficient with the use of LEDs instead of filament light bulbs, but they will still be consuming electrical power.
Although you can "ball park" the power consumption by adding up all the potential power consumers, you may still need to adjust this by adding additional boosters, depending upon the activities of the passenger and locomotive terminal. So, to allow for adding more boosters later, you can create several electrically isolated power districts and connect them together to one booster. If the district consumes too much power for the single booster, one or more of the power districts can be disconnected and connected to a new booster with its own power supply.
LocoNet will provide the DCC signal to each of the boosters and each booster will have its own power supply.