Drive hold.....

[LIRR]

What does this function do?

[Steveruger45]

Am assuming this is related to ESU Loksound decoders.
Here is a good explanation by streamline back shops.

Drive Hold:

This feature allows the modeler to easily simulate a loaded or empty train by adding a single "Drive Hold" function button. When the button is pressed, the motor will remain at a constant speed, while the sound can be controlled independently from the motion with the throttle knob! This exciting, new feature gives the operator the ability to
have his or her train crawl in notch 8 or coast at 50mph. Then, by releasing the Drive Hold function button you simply go back to throttle-controlled speed and motion. No more switching between manual notching and programming on the main to go back and forth. All of this can be done on the fly with hardly even thinking about it.

[conrad]

It also allows you to notch up the prime mover when the loco is stopped.  Release drive hold and the loco accelerates to the notched setting.  And, it works with consisted locos.

Conrad

[peteski]

But on many DCC throttles all but the whistle functions are latching.  Do I assume that on those throttles one would have to press and release the function button once to latch into the drive hold, then to exit the drive hold one would have to press and release the button (to turn off the latched function)?

[ednadolski]

Do I assume that on those throttles one would have to press and release the function button once to latch into the drive hold, then to exit the drive hold one would have to press and release the button (to turn off the latched function)?

That's how it works on my NCE throttle.  You can see the effect in the recent vids I posted, where the prime mover notches down while the loco continues to move at its current speed.   Then when I switch the Drive Hold to 'Off' with the throttle at Step 0, the loco coasts to a stop.

The only thing I find a little tricky is remembering whether I shut the drive hold off or not (since I also have the momentum turned up, it takes a bit of time for the loco to begin slowing after release).

There is also a bit of programming you have to do, if you want the drive hold to work with an advanced consist.

Ed

[reinhardtjh]

But on many DCC throttles all but the whistle functions are latching.  Do I assume that on those throttles one would have to press and release the function button once to latch into the drive hold, then to exit the drive hold one would have to press and release the button (to turn off the latched function)?

Yes.  That way you can simulate, say, the long grind up an extended grade or the long coast downgrade without having to hold the Drive Hold function button the whole time.  You can vary the diesel sound with the throttle know during this time to simulate increased or decreased load.

What the description doesn't make clear is that when the Drive Hold function is released, the motor speed increases or decreases to match the throttle (at whatever rate of momentum is programmed in the decoder).  So you would not in general do something like turn Drive Hold on, change the engine sound (via the throttle control) and then immediately turn Drive Hold off again as then the motor speed would change to follow the throttle again.  Unless you really did want a short time effect, then you would do that.  But that's not generally what it's used for.

[peteski]

Thanks guys - I wanted to make sure I understood how it works.  The way I understood Steve's description, it seemed that it might be designed for a non-latchign function button.

[LIRR]

thanks….I will give it a try...

[davefoxx]

But on many DCC throttles all but the whistle functions are latching.  Do I assume that on those throttles one would have to press and release the function button once to latch into the drive hold, then to exit the drive hold one would have to press and release the button (to turn off the latched function)?

On the ESU throttle (and in the LokProgrammer), you can set functions to latched or momentary.  For example, the horn is momentary.  Typically, Drive Hold is latched, so you turn it on with the press of a button and turn it off with a second press of the button.  Just like the bell.

An example of use of the Drive Hold feature, is that I will set Drive Hold while a locomotive is at idle.  Bring the throttle on the ProtoThrottle up to notch 4 to fill the air line.  Once that's done, I bring it back to idle and then can turn Drive Hold off, if I'm not going to move the train immediately.  Usually, I'll leave Drive Hold on, and bring it up to the desired notch when I'm ready to move the train, e.g., notch 8.  When I release Drive Hold, the train will start to move.  I can press Drive Hold to maintain a speed.  Once the train starts moving, I'll usually reengage Drive Hold to show the train creeping, and, meanwhile, the train's prime mover will sound as if it's in, for example, notch 8.  By turning Drive Hold off and on, I can control the speed slowly increasing, mimicking a heavy train, and the train will eventually come up to the speed where the throttle is set once Drive Hold is left off.  Once the train is up to the desired speed, I can also turn off Drive Hold (if it's engaged) and throttle back, if I don't want to run the train at ludicrous speed.

By the way, I also have the momentum setting on my locomotives set at about sixty seconds, which means it would take the model locomotive about sixty seconds to go from zero to max speed.

Hope this helps,
DFF

[jdcolombo]

By the way, I also have the momentum setting on my locomotives set at about sixty seconds, which means it would take the model locomotive about sixty seconds to go from zero to max speed.

Hope this helps,
DFF

LOTS of momentum is a key to using Drive Hold in the way Dave does.  Otherwise, the engine will "jump" up to whatever speed the throttle is set to far too quickly when Drive Hold is released.  Unfortunately, such high levels of momentum are disconcerting for operators who aren't used to that kind of setup.  If you are simply operating your trains yourself, or you have a regular crew that can get used to operating with high levels of momentum, using Drive Hold can produce some very realistic train movements.  But if you turn over the throttle to folks not used to that level of momentum, you are courting disaster.

Note that ESU decoders also have a "Run 8" and "Coast" function that can be programmed to function keys.  Both do pretty much as described: Run 8 maxes out the prime mover speed sound, but has no effect on throttle control; Coast essentially puts the prime mover in idle sound and also has no effect on throttle control.  While not as flexible as Drive Hold, you can use these two without the huge levels of momentum required to get the best effect with Drive Hold.  And perhaps save yourself a crash or two with inexperienced operators . . .

John C.

[CRL]

As kids, we had it much easier. Just make whatever sound you want to hear with your voice.

Adults try to complicate things way too much!