On a long heavy train with DPU 's cut in mid- train or on the rear, how does the engineer in the lead unit who has just crested a steep hill and needs to start slowing the front half of his train ( while the rest of his train is still going up the hill) keep the DPU 's pushing up the hill?
At what point does/can he start using the DPU’s braking ablities, ( dynamic, air)?
How is that command relayed to those units?
How was this (hill) manuever accomplished with manned helpers?
DPU equipt locomotives can be operated independantly or they can be operated where the trailing units do what the lead unit is. With them being controlled independantly the brakes & throttle can be set where ever the engineer sees fit for proper train handeling.
With manned helpers they just hook up to the train and help shove (or pull). They communicate over the radio but usually very little is said as the helper crews know what to do (which is for the most part is bring her up to run 8 and shove to the top of the grade). Where the helpers are placed depends on several factors like coupler force and where empties are. Depending on the situation a helper set may couple on the rear, couple on the front, or be cut in mid train. Cutting them in mid-train is undesireable as it consumes more time then the other options.
In dp I can control both uthe head and rear indepently just by doing what we call putting up the fence, I can have the head end in dymanic braking and have the rear in power, their is an 8 second lag from the head to rear both in power and dynamic.
Rodney
Rodney, what is the purpose of the 8 second delay?
That is how long it takes for radio waves and computer to respond.
Rodney
Gotcha.
Chad to expand on that the lead locomotive sends the command to the DPU unit which repeats the command back to the leader, which checks to make sure the command was received correctly, and then it tells the DPU to execute the command. Thats what takes the eight seconds.
Is the command center to control the dpu on the engineer’s control stand or is it incorporated in the led display in the newer units (i.e. Dash 9s)?
And does the power all have to be from the same manufacturer or the same (AC vs. DC) type power?
Will the information on the dpu unit’s performance (amps, temp. etc…) be available to the engineer in the lead unit? and can he shut it down from the lead unit?