Just a genral question, are mid-train loco manned at any time?
There is no need to have an engineer on distributed power units; they are controlled by the engineer at the head of the train.
Johnny
I have heard that, rarely, an employee might dead-head in DP. But they are not operating the engines, just along for the ride.
I have reported to the RR when I have seen a "passenger" that didn't seem to belong in one! I have no idea what happened after I reported it.
Semper Vaporo
Pkgs.
"Helpers", generally speaking, are manned. Distributed power locomotives, whether they are mid-train or on the rear, are not. Distributed power operations have eliminated most helpers. Montana Rail Link still uses midtrain helper units westbound out of Helena, Montana regularly.
Mark Meyer
VerMontanan"Helpers", generally speaking, are manned. Distributed power locomotives, whether they are mid-train or on the rear, are not. Distributed power operations have eliminated most helpers. Montana Rail Link still uses midtrain helper units westbound out of Helena, Montana regularly.
Where manned helpers are used, sometimes the helper needs to be cut into the train account 'trailing tonnage' restrictions on the grade being climbed.
Trailing tonnage restrictions identify the scenario where the head end power has the ability to haul more tonnage than the length and tonnage of the train will permit without 'string lining' and derailing account the trailing tonnage can 'pull the string straight' as the train attempts to negotiate curvature on the route.
CSX with manned helpers West from Cumberland sometimes have trains where the helper has to be cut into the train to climb the Sand Patch grade.
Never too old to have a happy childhood!
When I think of helpers, I think of locomotives added to a train to deal with a specific situation, ie, a big hill. Without that particular impediment, a given train can get over the railroad from A to B.
Helpers get/got added at the head end, in the middle (occasionally multiple locations), and at the rear. They were added at the bottom of the hill, and taken off at the top. In some cases this was done more or less on the fly.
Of course, there were myriad variations on the theme. Occasionally, if the profile was particularly trying, a helper might stay on the train for its entire run. In steam days, putting a couple of locomotives on the head end was referred to as double heading - and wasn't really considered a helper as such, even if functionally it was doing the same thing as would happen if it was added for a specific reason mid-trip. Just plain big trains would be the reason for double heading.
"Helper pockets," or some similar terminology, held the helpers until they were needed. Those might be stub end or double ended sidings. Sometimes there were turning facilities at both ends of a helper district, sometimes the helper(s) simply backed down the hill to wait for their next assignment.
As noted, helpers are manned. This was clearly necessary during steam days, but still applies since the helper is a short term assignment and will be returning to its start point to wait for the next train needing help.
From what I've seen, distributed power usually stays on the train all the way from A to B.
Larry Resident Microferroequinologist (at least at my house) Everyone goes home; Safety begins with you My Opinion. Standard Disclaimers Apply. No Expiration Date Come ride the rails with me! There's one thing about humility - the moment you think you've got it, you've lost it...
Norforlk Southern still uses manned helpers over the mountains between Altoona and Gallitzen, PA.
YoHo1975UP has a captive set of ES44ACs assigned to Roseville that get cut in at the head end of their big trains. I can't remember if they run to Sparks or Salt Lake, but in either case, They are not manned, nor DPU, but cut in behind the Train's main power up front then removed and the rest of the consist takes the train to the midwest.
On the territory I worked, such units were referred to as 'kickers'. They are cut in with the regular head end power at one location and taken out of the head end power at another location. They are fully coupled up to and operated by the head end power.
Union Pacific seems to have a diffferent set of perameters than BNSF for where and how they place DPU's in their trains.. At least the casual observation seems to suggest those proceedures (?) are unlike those of BNSF, at least in this area.
Where BNSF will generally use paired DPUs, UP seems to favor the single unit (?). Over in SE Kansas on the line south from KC area; even the run through BNSF trains will have two units in DPU, they seem to have only one unit operating(?). UP's trains always seem to favor a single DPU(?)
Many of the thru stackers on BNSF(Southern T-con) will operated with all their power on the head-end (4 or 5 units). The very, long trains with midtrain DPUs, (DPUs, will generally, be paired) and with a single rear-end unit ( Helpful, in maintaining train line air(?) The use of rear DPU's on the stackers seems to be confined to the ones with mostly Import/Export cans. Of course, the mostly TOFC consists do not ever seem to use rear-end DPUs, East or Westbound.
Trains over San Gorgonio Pass near Palm Springs would routinely operate with several sets of midtrain power as helpers (they were most certainly not intended as snappers!) and, of all the times I enjoyed watching the show from Hadley's, I never thought to notice whether or not some or all those sets were crewed.
I like the term "kicker" too.
CN calls them "float power".
Greetings from Alberta
-an Articulate Malcontent
The type and configuration of the power that a carrier uses to move trains is a function of the physical characteristics of the territory that the train is to traverse.
If the grades encountered are for intermittently sustained areas through the route of the train with minimal curvature involved. Head end power to the maximum tonnage rating would be the desired means of powering the train, If the train size is to exceed the allowed maximum head end power then DPU power will be used, either mid-train or on the rear.
If the ruling grades are of a short distance, it is more likely that manned helpers will be used. If there is a high degree of curvature in the grades where manned helpers are used it may frequently be required that the helper be cut into the train because of trailing tonnage issues with the train length and tonnage.
As an example, 2 AC units can easily handle 20K tons on CSX from Chicago through Willard and on to Connellsville, PA. To go East of Connellsvill to Cumberland assistance is required to climb Sand Patch grade and the helpers MAY be required to stay on the train DOWN Sand Patch grade for the additional Dynamic Braking the helpers can supply. If DPU power was used from the trains origination in Chicago to Cumberland - it would still ONLY BE NEEDED for the trip over Sand Patch grade, thus the units that would be placed on this train in DPU service at Chicago would accumulate almost 600 miles before they were needed for the approximately 50 miles necessary to climb and descend Sand Patch.
If there were grades every 50, 100 or so miles along the path of the train - DPU is the way to go as the DPU's additional power will be needed for each of the grades encountered.
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