BOB WALKER posted:There is no reasonable technical limit to the number of bluetooth engines that can be operated simultaneously from a single smart device. I have done four with my BlueRail engines. Lionel chose by design to limit single device bluetooth operation to one loco at a time. This, of course, could be subject to change.
This isn't exactly true. Because BlueTooth is a point to point standard, your phone actually has to open and close connections with each engine in a cycle. Typical low cost BLE chips shouldn't have much trouble talking to a dozen engines, but if you want to connect to a bluetooth speaker at the same time, you might have a problem. In the end it depends on the processing power of your device and the quality of the bluetooth transceiver it has. There will also be some practical limit in how many engines can be run based on the time it takes to cycle through connections. At some point it will take too long to run down the list before needing to check back with the first engine.
Bluetooth is an amazing protocol, but it's not actually a good one for talking to many things at once. Wifi, xbee, and zwave are all better suited... they just have the down side that your phone doesn't know how to speak on them.
