There are two LEDs in the circuit? The ~4V drop would be about right then, it's about 2.1V per LED for an ordinary colored LED. The Tortoise will be slow, but should be a lot quieter running on 8V. I would not go to a 16V wall wart - possibly a 14V one would be fine. 8-10 volts is kind of a sweet spot for a Tortoise where it still has enough power to hold the points but is much quieter than when using a full 12V. Just be sure that if you add more Tortoises, you install 2 LEDs with each of those as well, as 14V and 16V exceed the Tortoise rating.
The only other thing you can do is wire them to the contacts on the Tortoise, using a seperate power supply and resistors, so there is nothing between the toggle switch and the Tortoise motor connections. But this means a lot more wiring and complexity.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
If the Tortoise moves, then the circuit is OK. You showed two LEDs back to back, so only one is lit, thus you only have one LED in the circuit, the other is, as far as the circuit is concerned, not even there. Unless of course you have two LEDs lit.
LION DOES NOT DO THINGS THAT WAY.
LION has a HARD GROUND common running around the layout. One leg of turttle is soldered to the ground. Him cannont get away from the LION!
LION uses SPDT switches, one side of switch is -12vdc (Normal Position) or +12vdc (Reversed Position). The switch common is what I call the "stingger". It drives the terripin back and forth, it also will enervate any number of LEDS, relays and other appliences providing indicaation, signalling, and signal and track logic.
And LION only needs to run one wire to the hard-shelled slow-poke. On Layout of LION, with hundreds of wires, saving costs on wiring is a very big deal. ONE wire per turnout is enough. (After all, each station platform requires FIVE wires for the block signals and analog automation used by said LION. And him has lots of stations.
ROAR
The Route of the Broadway Lion The Largest Subway Layout in North Dakota.
Here there be cats. LIONS with CAMERAS
They are bicolor LEDs, so 2 back to back, depending on the polarity either the green or the red lights up (or other colors, there are other combos available now).
The same system would work with your wiring method, the LEDs would just go in series with the line leading from the SPDT toggles to the Tortoise motor. They key is that the Torise motor draws less current than the maximum allowed for LEDs, so you cna place LEDs in series witht he motor wires and not need any resistors. Makes for simple panel indicators or you can disguise the LED as switch lanterns and put one right at the turnout. Plus it means both sets of contacts on the Tortoise are still available for other things. Downside is it reduces the voltage to the Tortoise (not always a bad thing), and the LEDs light up dim while the Tortoise is moving and then brighten when it stalls - also not always a bad thing.