Philosophy Friday -- Double-Heading and MU Lashups

Model Railroader General Discussion (Model Railroader)
1

“Double-Heading and MU Lashups”

N&W Y6 Double-Headed - East of Blue Ridge, VA (From N&W Historical Society)

On the real railroads, double-heading-- or more probably nowadays-- multiple unit (MU) lash-ups are common occurrences. On model railroads double-heading often presents additional operational considerations that can make running multiple locos the occasional headache. For instance, if the speeds of the two (let’s say) locomotives are not closely matched, then one will pull or push the other which can cause problems with train handling, malfunctioning or breaking couplers, or even in extreme cases could cause one locomotive’s motor to wear out prematurely. When operating multiple units together there are really two components to consider, the physical match of operational characteristics between the units, and the subtlety of control available to fine-tune or compensate for discrepancies.

With plain DC control, since all locomotives operate from a common control and power source, the secondary control adjustments that exist with DCC and other onboard control systems, are not available. Thus the principle method of assuring good operation between multiple units lies in tuning and adjusting the physical mechanisms themselves. That, and making sure that locos have good motors, gears, etc., and are properly lubricated. One common technique is to make sure that double-headed / MU’d locos have matched gear-sets / gear ratios so that the motors and wheels turn at pretty much the same rate at the outset.

DCC, and presumably older methods of on-board train control, introduces the second

2

"So My Questions For Today Are:

– Do you run double-headers or multiple unit lash-ups on your layout? If so, do you do it regularly or only occasionally?

– What kinds of issues have you had to deal with with multiple units on your layout? Have you had any problems?

– Is your locomotive fleet of mixed manufacturer and vintage? If so, how has that impacted your ability to do multi-unit lash-ups?

– Do you have locos that just will not run together seemingly no matter what you try? Have you ever traded or gotten rid of a locomotive that will not “play nicely” with the others?

– What other issues, pro or con, positive or negative have you had with multiple unit operations on your layout?

– If you run DC-only, what kinds of adjustments have you been able to make to get your locos running smoothly together?"

As a modeler of a Class I double track railroad set in the Appalachians in 1953, double headed or even tripple headed steam and multi unit diesels are the order of the day - and I run long trains and use DC.

So to question #1 - regularly, almost every train.

Question #2 - No problems here, learned how to do this long before DCC was thought of, no need to change now.

Question #3 - Locos are a variety of brands, but most are from the last 15 years or so. Diesel lashups are mostly the same brand and model, as per common practice in the era I model. Most diesels still being used as “locomotive sets”. I have lots of EMD F units, and Alco F units, ABA or ABBA, lash up of 3-4 EMD GP7’s, etc.

Steam double headers are often matched identical units, BUT many are not. Here are some examples of different brands/types that run fine together:

Proto 2-8-8-2 run well with Spectrum 2-6-6-2

Bachmann 2-8-4 (converted to 2-8-2’s), Broadway USRA Heavy 2-8-2 and Spectru

3

I like running MU’s since it does add realism to running my trains. I run DCC if I am using mixed makes (Atlas and Athearn) it can take a little trial and error to match up the speeds. I use my base loco (in my case a pair of Atlas GP-38’s) . I adjust the CV’s up and down of the new loco while playing chase with my Geeps and when my loco can run my layout close but not touching my Geeps I know I am dialed in. I have one Atlas Dash 8 with sound that I cannot seem to get dialed so it is now used for pulling shortline local freight.

4

I always run multiple units on my layout. It varies between 2 and up to 5 locomotives.

I’ve never had any issues running multiple units. I did run a train with 3 Athearn Genesis SD75I’s and one Proto 2000 GP9 that was running the wrong way. I didn’t even notice it until I broke them up when I was finished a few hours later.

Most of my locomotives are anywhere between 1 year and 10 years old. They are mostly Kato, Atlas and Proto 2000 and hasn’t impacted my ability to MU them.

I do have a couple locomotives that are not happy when paired up, a Intermountain FP9 A and B unit. I don’t know why. One is a factory sound unit and one just has a simple decoder in it. I’ve played with CV’s but just can’t get them to “play nice”. I bought them to display them but it would be nice to run them once in awhile. I might work on that this weekend.

The only real issue I had was my own fault. I would run say 3 loco’s together and when I was done or wanted to run something different I would just stop the train, remove the loco’s and put them away. I wouldn’t unMU them. Later on, say a month later I would try to run one of those loco’s that wasn’t the lead loco and could never get it to move because I didn’t unMU and dispatch them from my DCC system. It would think it was still MUed to the others. I would do a complete reset of the decoder to fix it but it still wouldn’t run. Once I realized what I was doing I never had a problem again. That’s back when I was just learning how to use DCC.

5

1} I DO have a Bachmann {HO} FTA and FTB {DCC OnBoard} set in the B&O livery. I now run them together only now. after all, teh FTB unit would look funny pulling a train by itself, now wouldn’t it? {LOL}

2}There seems to be no probelms running these two together, but the were made to go together. I have yet to try My Bachmann DCC OnBoard GP7 with my Bachmann DCC OnBoard GP40 {both in Chessie livery} but now you have give me some thought…

3}I have ALL Bachmann DCC OnBoard in my fleet save one, and Athearn Quip plug-n-play loco that I’'ll be durned if I get teh DC “jumper board” off of to install the purchased DCC Card taht Litchfield station suggested the replacement DCC card for that loco! I believe I will sell the loco and the decoder on another site that allows buy&sell.

4}NO, but see #3

5} The pro is that the FTA &B look SHARP together! No cons with these two. They seem to run perfectly together. I will let you know how the GP7

6

Funny you should mention that. Here is a photo of a ‘B’ unit that was used by the Clinchfield RR specifically for moving around hopper cars at one of their coal tipples in Haysi Virginia:

(Source: http://clinchfieldcountry.com/photos/haysi.htm)

One of my Philosophy Friday posts awhile back mentioned it also: Philosophy Friday – How Do You Build A Locomotive Roster?

John

7

OBTW, there is a big difference between double heading and MU on prototype railroads.

Double (or triple or more) heading is when individual engines are combined, each with their own crews, each engine being controlled individually. That’s why a train is defined as " An engine or engines coupled…".

MU is when mutliple locomotives are coupled together and their control systems are linked to form ONE engine that is controlled by ONE engineer.

I think an iteresting question would be, those who “doublehead” your engines, do you actually double head them or do you MU them? If you have 2 steam engines on a train are they “consisted” (MU’d) or are they actually double headed with an actual engineer for each engine? When you add helpers, is there a separate engineer for the helper engine or do you just "add power’ and consist it in with teh regular power, using one engineer to control all the power?

For disclosure, I model the 1900’s so none of my engines MU and I have no grades so I don’t double head or help.

8

I have a pair of Proto GP9s that I almost always run together. I run DCC, and I tweaked the CVs to get a better speed match. So far, I’ve had no problems with this combination.

I run some F7 consists as well, but I have two powered F7As, a dummy A and a dummy B. The dummy B has sound and a working headlight. One of the powered As is currently out of action, and I’ve been doing scenery and haven’t gotten around to fixing it. I plan to put a Soundbug into the dummy B one of these days. They’re all old Athearns, although the one working F7A has a new chassis assembly I picked up a few years ago.

I run short trains on my layout, so MUs are not needed for power. On the other hand, I’ve noticed that the prototypes use MUs more than necessary, too, perhaps so they can couple them back-to-back and not have to worry about reversing the engines or running wrong-hood-forward on the return trip.

I do like to have at least one sound engine in a consist. Having sound in the second or third unit is nice, too, but I’d much rather have two half-and-half lashups than one with all sound and the other with none.

I don’t double-head my steamers, but I’ve got a question for those who do: How do you deal with the dummy couplers many manufacturers put on the front of steamers? Are they good enough to use for this purpose, or do you make that the lead engine, or do you put forth the effort to upgrade to Kadees?

9

I’ll answer the best I can using my club experiences since that is “my” HO layout.

1.Do you run double-headers or multiple unit lash-ups on your layout? If so, do you do it regularly or only occasionally?

Every time we operate I run a 2-3 unit consist.

What kinds of issues have you had to deal with with multiple units on your layout? Have you had any problems?

None…I minimize this by running Atlas with Atlas,Athearn with Athearn.

Is your locomotive fleet of mixed manufacturer and vintage? If so, how has that impacted your ability to do multi-unit lash-ups?

Oddly the older Athearn BB doesn’t play well with the newer Athearn RTR due to the speed difference-the newer RTR seems a tad slower and draws less current…

As a note of interest the older BB GP38-2/GP40-2 plays will with the RTR GP38-2/GP40-2.

Do you have locos that just will not run together seemingly no matter what you try? Have you ever traded or gotten rid of a locomotive that will not “play nicely” with the others?

Yes,but,most seems to play well with each other again Atlas/Atlas or Athearn/Athearn…No…Any odd ball gets assign to local or yard duty.

What other issues, pro or con, positive or negative have you had with multiple unit operations on your layout?

Nope-again I run like brands together.

If you run DC-only, what kinds of adjustments have you been able to make to get your locos running smoothly together?

No real adjustments like wiring the locomotive together etc.

10

Since I base my layout on a 16 mile short line and the longest train is seven cars, only one locomotive is used with each train. I’ve toyed with the idea of dedicating two Atlas S1’s for a short 10-12 car stone train, with one locomotive at each end of the train like a push pull arrangement. Sort of a short line version of a modern BNSF Powder River Basin coal train:-). Each loop of the dogbone would represent a short balloon track, one loop for loading and the other for unloading. The locomotives would never uncouple and since they are very much speed matched from the factory, nothing special is required to get them to run together just fine as they are. That’s about as close to multiple unit consists I will likely ever get.

11

Well. here on the ATLANTIC CENTRAL all steam locos must have working front couplers. So ones that come with dummy front couplers get rebuilt as needed. Not a big deal in most cases since ALL rolling stock and locos get genuine Kadee standard head couplers before going on the layout. No generic couplers, no semi scale couplers - good operation is first priority.

A few more thoughts on the subject while I am here:

I don’t concern myself with the position of tthe faster/slower loco, it never seems to make that much difference. My trains are long enough that two locos are needed on the grades and train weight makes everything smoothout just fine.

Some mixed brand steam starts are just a little “bumpy”, but same was true of the prototype in steam days. Start slow, let everybody get going, works just fine. Only well matched locos are run together at higher speeds, no different than the prototype.

I don’t do any pushers or mid train stuff, not that it does not work, I know lots of guys who do it in DC, it just does not interest me of fit the operational scenerio I have delveloped.

Sheldon

12

Interesting topic this time.

I MU locomotives together during my operating sessions (DCC consist). I should say my ‘engineers’ MU the loco’s. I run NCE DCC and it is really easy for them to do. They are only MUed when required. Other than that, switching is done with the same locos when de-consisted.

My locomotives are all different manufacturers and decoders that I have installed myself. The oldest loco is a Roundhouse RS-3 that I got somewhere around 1987 or so. It was my first DCC loco and I hardwired a Soundtraxx decoder in it. It is still running strong. The newest loco I have is a Life-Like proto 2000 with a QSI sound decoder in it that I bought two years ago. I put a GP-9 shell on it. These two engines run well together. I also have Atlas and Walthers Train Line loco’s.

I use JMRI Decoder Pro to speed match all of them, and I use the ‘user’ speed table to do it.

I don’t really have any major problems to speak of. Everything seems to work fine. I do have an older Life-Like BL2 that has the bronze wheels. It seems to need a bit of a ‘warm up’ before it gets consisted or it seems to be a little sluggish at first.

I haven’t had to get rid of a loco yet because it wouldn’t consist well. I am sold on Decoder Pro.

13

I run mostly diesels.

My current standard is an Atlas engine fitted with a TCS decoder, Back-EMF on. I put the decoder in and run it. Other engines get matched up to this. For the Athearns, a reduction of mid and top speeds gets things close enough to work fine MU’ed. Most everything has a TCS decoder. The few that don’t are kept together.

The one problem child is the P2K GP9 with QSI sound. For the life of me I can’t it to run with the standard, and it doesn’t pull enough on its own to be worthwhile, and I’m not impressed with the sound, either. An older non-sound drive has been acquired, just need to round up the proper fuel tank and the the sound drive will go away.

14

Road switchers and road freight units: at least two on the head end of a train. In my opinion, one road loco by itself looks like I’m running a toy train set.

Speed mismatch due to gears and driveshafts slipping or binding. I had one loco with a horrible gear problem, but fortunately I had some spare gears from a loco I dismantled years ago and I was able to fix it.

Some loco sets are matched pairs .(e.g two GP7s or two RS-3s). Other sets are mixed (e.g. one RS-3 and one H16-44 or one RS-1 and one DRS-4-4-1000). In those lashups the RS-3 is Atlas and the H16-44 is Bachmann. The RS-1 is Atlas and the DRS-4-4-1000 is Bowser/Stewart.

An ornery loco that won’t run with anything gets converted into a dummy loco.

Speed mismatch. But the rule of thumb is to run the faster loco first and have the slower one trailing.

Same as above.

15

I run multi unit consists all the time except for yard ops.

The Issues I have is typically with the initial set-up. Whether the loco is the same manufacturer or not I try to keep all of the loco’s that may run together matched for speed.

All 6 axle loco’s are set to the same speed curve and the same with 4 axle. That way when I decide what I will run I know they’re already set.

A couple didn’t match to easily and needed custom speed tables. This typically happens when the basic settings are different. Some have vmin vmid and vmax. Others have vmin only and others again have vmin and vmax.

If running DC only, the best adjsutment you can make is to switch to DCC [swg]

16

Question #1 - all road trains have 3 locos, all locals over 8 cars have 2 locos.

#2 - None. All locos on the layout (150+) have been speed matched using DCC. Any loco MU’s fine with any other loco.

#3 - Most locos (80%) are Kato or Atlas. Remainders are Proto2000 and Athearn. No issues.

#4 - None.

#5 - No issues, works great

#6 - n/a

Layout was built with a goal of running MU locos.

17

Since the this topic migrated slightly to the thread about the future of DC, I thought maybe I should post this additional info here as well for anyone not following both:

Regarding MU and double heading with DC:

I model 1953-54, my railroad, and many protoytypes in that time period, still ran diesels pretty much as matched sets.

However, fact is all the following locos have basicly the same drive and will run together fine - Early to mid production Proto2000 BL2, GP7, GP9 (actually most all the GP series, but the rest are out of my era), and ALCO FA1 & FA2.

All Athearn Genesis F units have the same drive, so F3’s and F7’s readily interchange - that’s about as much mixing as most prototypes were doing in 1954.

As for the steam, it is trial and error - BUT most manufacturers are using similar gear ratios - so locos with similar sized drivers often run fine together - regardless of brand.

I will restate the matchups I regularly use - Proto2000 2-8-8-2 with Spectrum 2-6-6-2, Bachmann 2-8-4 (now 2-8-2’s on my railroad) with spectrum USRA Heavy 4-8-2’s - and either of these will run with my BLI USRA Heavy 2-8-2’s.

Actually at that point we have covered a large section of my loco fleet because it is made up of multiple copies of a select list of wheel arrangements and types.

With a little careful throttle work at startup, Spectrum 2-8-0’s can be run with any or all of the steam listed above.

The above listed steam locos represent a total of 26 pieces.

Now we are left with only a few more steamers, two Spectrum 10 wheelers and three various Pacifics usually run alone on local passenger trains, two Reading T-1 Northerns, a 2-6-6-6 and a 2-6-6-4 that don’t need helpers or doubles, and some switchers.

So out of 38 steam locos, 26 of them can be grouped in double or triple headers at will without regard for brand or wheel arrangement. and other matched sets like the 10 wheelers or Northerns ca

18

while I’ve yet to really run any of my locomotives together, I do have a Athearn BB GP40-2 and a Bachmann DCC Onboard SD40-2 that actually seem to run just fine together. Of course, I also have the front driveshaft on the BB removed due to a missing worm gear assembly for that truck (dunno where it went, it just “evaporated” one day back in my teens), and of course the GP40-2 does pretty well pulling 10-15 cars by itself so I can use it for “yard” duty too, but overall those are my best two running locos, therefore, they’re they only two I’ve actually tried to run together. Going to be procuring several more locomotives in the near future, so we’ll see what happens when I get them. As of right now I’m really just starting back into the hobby so I’m using what I had when i was 11-15, which is a Tech II or III powerpack and going from there. Will eventually convert to DCC but that will wait until the layout is fully complete.