Use of engines and helpers?

Caught a video recently of a huge coal train out west and noticed two engines in the lead , three in the middle followed by a single at the end.
Always wondered how it’s determined to build a freight and how is all the power controlled?
Thanks
Mark

Not an expert but here is a brief description which says "distributed power" is remote controlled from the lead cab. https://www.trains.com/trn/news-reviews ... locomotive
I don't know if it is automatic (all computer-controlled based on the lead engines, for example) or the engineer in the cab has to set the mid and rear engines individually.

Railroad operating departs (especially the class I's) will have published rules that govern train makeup, how much power can be online, how many operative dynamic brake axles can be cut in, position of mid and rear train helpers, etc. The rules can vary considerably depending on the railroad and the specific territory.

As for DPU control, the DPU can be setup operate in tandem with the lead units, meaning that when the engineer moves the throttle to, say, notch 3, the DPUs will also go to notch 3. Or they can set setup a "fence" and control the DPUs independently from the lead unit. While the engineer has considerable leeway in how to run things, I believe the software will prevent certain combinations of settings (like having the lead unit in throttle and the DPUs in dynamic brake).

Note that the brake pipe is still continuous through the train and through the DPUs. If the engineer makes a set on the lead unit, the whole train will react accordingly.

Thanks to all.

Seems the engineer would have his hands full !

On grades wasn’t it previously mentioned that the crew would also have to monitor the ‘tension’ (for lack of the proper terminology )along the length of the whole train ?

Maybe I am stating the obvious, but I think reducing "tension" as you call it to reduce broken couplers/ knuckles was indeed a main motivation for distributed power.

Yes, reduction of "In train forces".

DP was not directly about reducing in-train forces. DP was about running longer (and heavier) trains. Max train lengths before DP were approaching maximum allowable train forces, so running even longer trains required helpers to keep forces tolerable, not the other way around. DP evolved in part from the problems that surfaced with RC helpers - loss of communication between head end and rear end - since the rear end helpers were at the rear of the already too-long trains, and often comm failures were exacerbated by tunnels and other features. Moving the helpers to mid-train (now called DP) helped solve the problem, but not entirely. The radio technology had to evolve a bit too during that time period.

Strictly speaking, the current iteration of DP isn't true DP, it's really still just remote RC helpers. True DP is a more even distribution of powered axles throughout a train, like every car or every few trucks, powered (in some versions) by a common power source or smaller, localized power cells. The economics of that system haven't been justifiable in the current world though, so we have the remote helper version.

Again thanks for educating me ,,,,,

Ok let’s go to steam helpers on the coal freights let’s say on the Elmira Branch headed to Sodus Bay .
I reference this only in that I’m familiar with the area and history of that branch so I’ll bring my previous observation about the lead engineer coordinating with the helper(s).

DPU is sort of they couple two trains together and run all the engines from the head end. Sometimes a rear engine is added.

Conrail actually tried this in like 1995-ish, a group of maybe 20 C40-8Ws had a Locotrol system installed and they'd run 200 car ELSE's with it. But they eventually gave up as the technology wasn't there yet and they broke a lot of knuckles with it.

Now, I see them running DPUs even on the roller coaster profile going up to Watertown and Massena. Thinking it has to be challenging for train handling when part of it is going uphill and part downhill and there's an engine pushing halfway through.

Conrail's Locotrol DP experiment was 1990-1992 (the 6050-6059 built in 1990). I ran a rather large BUOI with it from Buffalo to Gang Mills. Didn't break any knuckles (or anything else) with it, and there's a lot more roller-coaster to the Tier than the Water Level Route. The biggest problems with it then was what I referred to earlier with radio comms (I had little to no trouble with it) and absolutely no training on it what-so-ever before my trip. I do recall the Trainmaster at Frontier asking if I was OK with trying it out before we got on and doubled out. And yes, it took a fair amount of brain power to keep the train forces constantly updated in your brain while manually controlling two sets of power and still watching signals and blowing for xings etc.

eolesen - Track speeds and turnaround times? LMAO. DP is about anything but, regardless what they tell you. It takes a lot longer to put together and dismantle monster DPU trains than traditional trains, and track speed means very little nowadays. RR management today is all about fewer people moving more freight. If it takes longer and costs less, they're (the stockholders) happy with the bottom line. Customer service is so bad the STB is intervening far too often due to customer complaints.

Fireman43 - Steam obviously had separate crews for each engine, no matter how many were on a train, and communication with helpers was by whistle signals and air signals. They would, depending on circumstances, signal readiness by making air reductions/releases to signal the helper. Conductors also had brake valves in the caboose on some roads so they could make reductions or control the charging at the rear. For instance, the conductor could hold the brake pipe at a lesser pressure on the rear (still high enough to do the brake test), and when they were ready to go he would signal the head end by closing the valve, which signaled the head end by bringing the brake pipe pressure up to normal on the engineer's gage. If the rear end decided they needed to stop at the next station, they could use the caboose valve to make a reduction, signaling the engineer that way.

Elmira Branch - Helpers were usually I-1s and L-1s. All with short tenders as the big tenders wouldn't fit on the wye tail at Starkey. A couple of pics at Watkins

jurtz wrote: ↑Thu Jan 26, 2023 2:48 pm Railroad operating departs (especially the class I's) will have published rules that govern train makeup, how much power can be online, how many operative dynamic brake axles can be cut in, position of mid and rear train helpers, etc. The rules can vary considerably depending on the railroad and the specific territory.

As for DPU control, the DPU can be setup operate in tandem with the lead units, meaning that when the engineer moves the throttle to, say, notch 3, the DPUs will also go to notch 3. Or they can set setup a "fence" and control the DPUs independently from the lead unit. While the engineer has considerable leeway in how to run things, I believe the software will prevent certain combinations of settings (like having the lead unit in throttle and the DPUs in dynamic brake).

Note that the brake pipe is still continuous through the train and through the DPUs. If the engineer makes a set on the lead unit, the whole train will react accordingly.

This is how I was told by a few of my NS engineer friends. I thought of this after that conversation and haven't seen them since to ask. I know it would probably be a rarity, but:
In the event that the DPU train would need to switch out a midline customer enroute with an opposing switch, can the train be broken where needed and the switch be made remotely with the DPU power at the rear powering the switch remotely from the front end, or do the locos have to be manned by the engineer in this case like a split power local either by rule or by capability?

Can't say I know for certain, but I have to believe that operating a locomotive remotely using DPU controls for switching purposes would not be allowed. The main reason being DPUs typically are setup to maintain their current throttle settings in the event communications (COM) are lost. The last thing anyone would want is for a remote to lose COM and just keep moving in the middle of a switching or shove movement.

DPU is a different animal than the remote belt packs that are often used in yards. I'm pretty sure if the remote belt packs lose COM they are setup to stop the movement. I know they will stop movement should the belt pack sense that the operator has fallen down.

jurtz wrote: ↑Wed Feb 01, 2023 3:24 pm Can't say I know for certain, but I have to believe that operating a locomotive remotely using DPU controls for switching purposes would not be allowed. The main reason being DPUs typically are setup to maintain their current throttle settings in the event communications (COM) are lost. The last thing anyone would want is for a remote to lose COM and just keep moving in the middle of a switching or shove movement.

DPU is a different animal than the remote belt packs that are often used in yards. I'm pretty sure if the remote belt packs lose COM they are setup to stop the movement. I know they will stop movement should the belt pack sense that the operator has fallen down.

That makes sense. Thanks.

I just remember Conrail running those monster trains for a couple of months and then they went away. Crew I talked to mentioned three knuckles just trying to get one out of Buffalo. I concluded on my own the tech behind it wasn't quite there, but the unions could just as easily have said we're not doing this. Too long ago to be certain.