A Guide TO Dcc Page 13 A Guide to DCC

13 all respond at the same time and with the same commands. The command station is not bogged down tracking MU consists and data traffic on the DCC signal is reduced. Most modern decoders offer advanced consisting. What is right for you? It really depends more on your system. Some systems are set up to prefer operating with one mode more than others. Advanced consists keep the units consisted, even if there are problems with the controller or otherwise. The principle complaint of this system is the consisted address is generally not the same as the lead unit number; a new number is generally assigned. Universal consisting allows you to keep the lead unit number in controlling the consist. Of course, the down side is if the master controller becomes confused or someone accidentally clears the consists out, all the consists on the layout will have to be reprogrammed back in. Any system can use basic consisting, however as was mentioned, it offers the least lexibility in terms making up and breaking up trains as well as in the ability to make any CV changes on the fly by using programming on the main. Consisting allows layout owners to take advantage of one of the key advantages of a DCC system to run locomotives together on the same track and at the same time. With consisting, you can truly lash up a set of your favorite locomotives and get them to run together simply and efficiently. And if they have sound, you can recreate that feel of power as the units spool up and accelerate that train out of town! Momentum and Braking On the prototype, the engineer notches up the throttle, the prime mover starts ramping up in speed, the generator is able to generate more power, this power transmits to the traction motors and the loco starts pulling. Once the tractive effort is applied to the rails, the force is applied to the 5,000- 10,000 tons of train, and slowly accelerates. All this takes time and delays the startup of the train from when the throttle is originally moved. Energy has to be put into the train to start it moving, slowly at first, and then more quickly. All the while, the prime mover is screaming along. When stopping, the opposite happens. Shut off the power, and the momentum of the train will continue to carry it forward. Until friction, either by the brakes or by the train itself, overcomes the momentum, the train will continue to roll. These effects can be easily simulated in a DCC decoder. Additionally, without momentum, you cannot simulate the sound of the momentum without manually forcing the sound decoder to ramp up and down independently of the speed controller position. The reason the engine does not load up before moving is because there is no way the prime mover sound knows that you intend to move before you spin the knob and expect the loco to move. Or said another way, you need momentum to simulate a heavy locomotive. One solution is to manually change the prime mover sound while running the loco. Not very much fun, and not very realistic. A lot of function key pressing is required to play with the sound, not something a real locomotive engineer would ever do. Besides, if the operator gets busy, they will tend to not do the manual notching and all the realism foes away. Both the feel and sound of a heavy train can be easily programmed into a DCC decoder. CVs 3 and 4 define the acceleration and deceleration curves. Additionally, with sound decoders, the prime mover has to spool up before the train really gets going, and similarly, the prime mover will spool down to an idle before the train stops. The resulting effect is very realistic. Braking is a bit of a different option. With a high deceleration rate programmed in, the train will continue to drift for a while after the throttle is turned down. Depending on how much deceleration is programmed in, it could roll for quite a while before coming to a stop. Some decoders offer a braking feature that can be programmed to one of the F keys. When pressing this function, the rate of deceleration is increased by some factor, and the train will stop more quickly. Braking values can be set so high that it effectively can act like an emergency stop button! Ideally, when set up with momentum, the braking function will reduce the distance needed to stop by 1 /2 to 2 /3 of what it would have been without braking. Before setting up locomotives with momentum and braking, it is very important that all other elements of the operation of the layout be tuned perfectly. There is little more that is frustrating to be dealing with momentum and braking when the train stalls at every turnout or on will not run smoothly on straight and level track. Rolling Stock With all the aforementioned elements of DCC in locomotives, it is only logical to apply the same thoughts to other rolling stock. Function only decoders can be installed in cabooses and passenger cars to control interior and marker lights. Some manufacturers are now offering decoders to create the sounds generated within refrigerator cars or even live stock. Opportunities are only limited by our imaginations. Perhaps a motor and decoder could power the blades of that rotary snow blower, maybe even with sound. Some hobbyists are now using decoders to control motors that move the arms of a brakeman holding an illuminated lantern riding on the platform of a passenger car! The sky is the limit. Sound decoders are available with freight car and environmental sounds. Imagine this scene with mooing coming from the stock car, pens and locomotive.

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