Directional lighting means that
the front light will be on when the loco is going forward and the
rear light will be on when the loco is going backwards. They will
never be on at the same time.
With traditional DC Analog control,
directional lighting can be achieved by using a pair of diodes. Since
diodes allow voltage to flow in only one direction, the diode controlling
the front light would allow electricity to flow only when the polarity
was correct to make the loco go forward. Same for the rear light,
only for going backwards.
Also with traditional DC Analog,
lights typically get brighter as the train goes faster. That's because
the voltage on the track is higher to make the motor go faster. Constant
brightness lighting can be achieved with the use of more diodes. When
running the motor power through a couple of diode pairs, there will
be 1.4 more volts on one side of the diodes than the other. This voltage
differential can be used to light 1.5-volt bulbs. But still, if the
loco is stopped the lights are off.
With DCC, track power is on at a
constant voltage all the time. This means you have constant brightness
lighting without special motor diodes. It also means you can have
lighting whenever you want it - even when the loco is stopped. In
fact, you have full control of lighting at all times - even to a point
of having special lighting effects.
When you turn the lights on, they
are on at a constant brightness - even when the loco is completely
stopped. Further, they can be programmed or wired to be directional,
non-directional, even dimming. And with the right decoder, you can
also have many other special lighting effects such as Mars lights,
strobes, Blinking Ditch Lights, and more. In fact, with the right
decoder(s), you can have head and tail light, Mars light, ditch lights,
running board lights, truck lights, cab lights, and number board lights
- all individually-controllable if desired.
When you turn the lights on with
a decoder that has directional lighting, the front light comes on
when the loco is going forward. When you reverse the direction the
front light goes off and the rear light comes on, and vice versa,
even when the loco is stopped.
Most decoder manufacturers provide
directional lighting on their decoders. The companies that do not
provide directional lighting say that it is not prototypical so they
don't provide it. Having that kind of attitude is very short-sighted.
There are, in fact, some roads that do have directional lighting.
And with directional lighting you can wire it for non-directional
lighting, even prototypical dimming if desired. This is something
that can't be done without either directional lighting or a special
effect to do so.
First and foremost, many people want
directional lighting simply because they want the front light on when
going forward and the rear light on when going in reverse - and they
don't want to have to change it manually. They want this not just
for the lighting, but also for visual feedback so they will know which
direction the loco will go when they give it throttle. While there
is an indicator on the hand-held throttle as to which direction the
train will go, many people don't look at their throttle when running
trains. Instead, they've learned which buttons on the throttle does
what and can run the train without having to look at the throttle.
By having the lights on the loco change automatically with the change
of loco direction, this gives them the feedback they need to assure
them that the train will go in the direction they want - without taking
their eyes off the train to look at the throttle. This gives them
more time to watch the trains run - which is what DCC is all about.
It's as simple as that. They don't care that it's not prototypical.
They're having fun running and watching their trains - it's a major
convenience. |
