Question, on the older Diesel sets the Lead engine had direct connections into the controls for the additional units, with distributed sets, 2 or 3 lead, generally One center and one trail how are the controls established engine to engine to keep them consistent in power gradient and how are controls indications/trouble indications delivered to the Lead? Was a mechanic on Heavy Equipment and trucks for YEARS, this is beyond me.
Specific locomotives in each carriers fleet have been equipped with the necessary electronic and other equipment to be operated in DPU. As new locomotives are purchased, most are being equipped with the necessary DPU equipment. The primary requirements are that the Lead locomotive on the train be DPU equipped and one of the engines back in or at the end of the train be equipped with DPU equipment. The normal MU connections between locomotives will allow locomotives coupled to the DPU equipped locomotives to be operated under the control of the DPU equipped locomotives on either the head end or in the remote locations. Properly configuring the DPU locomotives is necessary and must be checked. It is possible, if not configured correctly, for one locomotive set to be operating forward while the remote DPU set is operating in reverse.
Now that's a scary possibility. Does that happen often, or was it only a part of the early years learning curve for DPU? Somebody posted a photo a few years back of track damage where a DPU remained in Run-8 after the train had been stopped. The damage showed the rail head and web melted down to the rail foot in twelve places, under each of the wheels of a six-axle locomotive.
A DPU consist consists of a controlling unit and a DPU equipped unit in each of the trailing consists. The DPU units communicate by radio and the other units coupled to the DPU use the conventional MU connections. Each trailing DPU set can be controlled individually by the engineer on the lead DPU engine.
He is exactly right. Say you have a train that needs an A,B,C or more sets, distributed thru ought the train. On the H/E there is a screen that will accommodate the operation of these B/C/D sets, they can each be made to be in power, brake, idle from the H/E, as the poster indicated, multiple units in the B/C/D sets will operate at the H/E or A engineers request. It can get complicated, but when it works, it works good. When it don't work, it's an epic fail. Expect to re-crew trains for 100's of miles in either direction.
That could easily have been from just a regular MU hook up - engine 'back' in the engine consist loses contact with the 'shut down' pin on the MU cable. The 27 pin MU cable carries a variety of electrical control actions - failure, while rare is not that rare.
Interresting. So, with these features, what happens with, say, an heavy and long train with a H/E set and a helper DPU aft, when this train is cresting a hill ? So when front part of the train is downgrade and aft part upgrade ? Can the engineer idle his H/E power (see set it into dynamic breaking) and have his helper set still pushing hard in run 8 ? Or the opposite when his train is downhill in a bottom ? Dom
Hi Dom, Short answer is yes. You can have your HE in dynamic and B,C in power if you want. Often times on a train that has a lot of MTs on long descending grades the dynamics won't hold it and a minimum set is too much, the DPs can be set to idle and keep the HE in dynamic to keep the slack from running out. Even put the DP in a little power to get you over a flat spot without having any run outs. All kinds of combinations possible.
How do y'all keep your wits about you with the transitions involved that Dom describes? So much happening at once and with enormous tonnages pulling and pushing at the same time, and all the while changing. One miscalculation and a knuckle breaks or worse. My hat is off to you guys, doing this safely, hundreds of times a year and at all hours.
Thank you gjslsffan for your input. But then, a subsidiary question : as far as I know in every locomotive you have one throttle, one dynamic brake control, one train brake handle and one locomotive brake handle. In this case, how an engineer can have differential control between his H/E locomotive/set, and DPUs further on down his train ? Dom
Within the DPU software on all the DPU equipped locomotives the engineers are able set up a 'Electronic Fence' that allow him to make necessary operating control changes to each set of the DPU units within his train SEPARATELY. The engineer controls whether if the Fence is up or down. Fence up and he can have different control inputs to each DPU set; fence down all DPU sets operate in unison.
