Can I run Atlas and Kato engines together?

On 2/2/2008 5:39 PM matrixn spake thus:

This is an excellent question, to which I unfortunately don't have an answer. (Lots of replies will be along soon, though.)

As long as we're on the subject, how does this work in the Real World? I mean, locomotives probably have different pulling powers when lashed up, so does it matter that the lead loco wants to go 79 mph while the one behind only wants to do 65?

If the speed difference is large, I would advise against it. If the speed difference is small (ie, the faster engine creeps up on the slower one when you run them a few inches apart), then it's OK. Large speed differences cause driving wheel slippage on the faster engine, which means higher power draw, which could overheat the motor.

BTW, perceived speed is illusory. You are watching the N scale trains from 300 or more N scale feet away, that's the length of a football field. At that distance, speed looks slower. To estimate the speed of the train, count the number of 50ft (scale) cars that pass a given point in 10 seconds. 10 cars is about 60scale mph. 5 cars is about 30 scale miles per hour. Etc. Modern freight trains generally cruise at 40-60mph, and often run much slower.

HTH

I personally have HO scale and wondered the same thing when I was new to all of this. That was 13 years ago. Now what I have seen, before I switched to DCC, is when you lash up different model from different manufacturers they do run together. If you look at the couplers between the engines and they have no slack, i.e. the front engine is pulling the rear engine or the front engine is being pushed by the rear engine then they are not matched well to run together. But if the couplers alternate tight and loose that would be desireable. As with most question posted like this everyone who answers will have a slightly different answer. Hope this give you some insight George Fernandez

"matrixn" wrote

As you already figured out, the faster engines should always run in front. But if there is a large speed differential you're better off not running the locos together at all. The best that can happen is that the lead locos will be spinning their drivers all the time and wearing all the plating off of the wheels as a result. As Wolf mentoned, it might overheat the motors as well, although I've never yet seen that happen.

The *worst* thing you can do is to try and run the faster locos as mid-train helpers. As you increase the train's speed, the speed differential between the different units will increase even further and the cars between the front units and the mid-train helpers will derail and accordion at the first opportunity.

I once had this happen on a 106 car ore train when the lead units had entered the next block and an inattentive club member -who shall remain nameless- (Roger) reversed the polarity (Roger) without first checking to see (Roger) if the block was indeed empty (Roger)...

The good part is that the resulting pile-up yielded a wonderful photo of fifty-odd ore cars zig-zagging all over the layout!

Pete

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The thing that is throwing me off is that if I run the engines without any box cars they run faster. This is common sense in that they do not have to pull any load. Here is an example:

Atlas running the track by itself = 60 mph Atlas pulling the 36 cars by itself - 0 mph - it actually doesn't in my case

Katos running the track by itself = 50 mph Katos pulling the 36 cars = 35 mph

Atlas + Katos pulling the 36 cars = 45 mph

So in the above, if I run all three, the Atlas is -15 mph their optimal speed and the Katos are -5 the optimal.

So I'm inclined to think that this configuration is OK and that -5 is better than -15 for the Katos and obviously -15 is better than -60 for the Atlas.

BTW, thanks for all the replies everyone. I *think* the answer is to have enough engines running similar speeds so there is no effective slowdown. I did have one more question. Will an engine always spin it's wheels if it can't run at optimum speed or will the wheels slow down? I'm curious if my wheels are spinning while pulling all the cars. I ended up just going with the two KATOs to pull the 36 cars for now.

"The good part is that the resulting pile-up yielded a wonderful photo of fifty-odd ore cars zig-zagging all over the layout!"

That would definitely be a site to see. I have an 85 foot track going around the ceiling of my room. I cringe when a car derails because it usually means it dropping about six and a half feet down to it's doom. Luckily in most cases it hit's carpet, but there's brick in one stretch and some other not-so- kind areas along the way. My current goal is 50 cars, then I'm sure it will be 75 and then 100. I think 100 will be my limit for one train. I wonder how many engines I'll need for that...

I had a decent sized N scale layout, and used to run some monster trains with almost 100% success, but once in a while, there were some pretty amazing wrecks. I had a bunch of the same locos, and they varied widely. I don't remember who made them, but I had 4 PC FA-1's that came from 2 production runs, as the motors were different. The older ones were much slower than the later ones, but the paint on the newer ones was a little better (Sharper PC logos) Two of those could pull, once it got started a

100 car train pretty well. The wheels spun at first, but would eventually grab and off the train went. My Con Cor PA-1's could outpull anything else I ever had. I had every car I had behind those two locos, so many the caboose, well, the last one anyway was about 3" from the front of the train when the slack stretched out. Coupler snapping was frequent. I wish I had a decent movie or video camera then. The wrecks were fun to watch,and the damage usually wasn't too expensive to fix.

BDK

So you were able to run two engines of different speeds when pulling this amount. Excellent. My two Katos seem to be pulling much better than yesterday when I first started. There was a train swapmeet yesterday so I picked up 11 cars and the new engine. An interesting thing is I swear the track and trains need to settle to run smoothly. Whenever I swap the engine from Kato to Atlas or back I almost always get a couple of derailments or couplers de-coupling but eventually it all seems to settle in and run smoothly. It's probably because the track runs on shelf I have going around the whole room and I have 9" curves I believe. I forget the exact dimension but it was not the smallest but one up. Because of the tighter curves I can't run longer boxcars or engines (mainly the long passenger trains), but standard engines and freight cars are fine.

The reason they run slower when all the locos are together is because you have more locos drawing power from your transformer, therefore reducing the effective current available to each one.

Oh, sorry about not clarifying, I meant with more box cars. So if I have one engine running by itself (not pulling any cars) it goes faster than when pulling 30 cars. Does this mean the wheels are spinning a little or are they actually slowing down due to the pull load? Note, just one engine in this case. The only difference is the number of cars it's pulling.

On 2/3/2008 12:08 AM matrixn spake thus:

Another good question, and unfortunately again I don't have an answer. But I will say that I'm extremely skeptical of the claims given here that mismatched locomotives will cause the higher-powered one to spin its wheels (talking about models here, not the Real Thing).

Think about it: the difference in force here is tiny, and hardly sufficient to cause wheel slip in a locomotive. Unless someone can report having actually observed this, I'm going to file it in the Model Railroad Mythology folder.

"David Nebenzahl" wrote

Um, David, I've seen it happen on multiple occasions, both with my own trains and those belonging to others as well. I don't think it's unusual at all to see one or more units slip their drivers because of mis-matched speeds.

With diesels it's sometimes difficult to tell, because the wheels are pretty much hidden behind the truck frames, but if one or more units are slipping you can often *hear* the wheels of the faster units chattering on the rails. As one example, I've discovered that my Atlas SD-35 units slip wheels and chatter when run with my Overland brass, and the throttle is advanced to more than about 1/4 of the way up.

With steamers there's no doubt about it at all, and when you're double-heading you can *clearly* see the wheels of the faster loco rotating at a notably higher RPM than those of the other.

To prevent this from causing problems, I've compiled a list of all my locos in order of comparative speeds at the same throttle setting, and consult the list to avoid hooking up locos that run at significantly differing speeds.

(Example: Were I to run my very quick Balboa GS-2 double-headed with my Westside GS-4 -which is a decidedly slower loco- the GS-2 would slip everywhere except on the steepest grades, where the GS-4 would be unable to pull the load by itself.)

This isn't just a guess. It's the results of running heavy trains up considerable grades with multiple units for years and years and watching the results.

You're invited to visit our club and observe for yourself any second Saturday of the month.

Pete

I built my own track cleaning loco around two motor bogies, one of which ran very slowly and the other very fast. I put very little extra weight on the fast running end. The fast turning sintered metal wheels do an excellent job of polishing the rails and the rear bogie with two rubber tyred wheels and extra weight sets the operating speed.

When rubber tyred wheels slip they make a horrible noise! (that's a seperate observation from the track cleaning loco)

Greg.P.

No, I ran pairs of identical locos, I had 2 slower FA-1's and 2 faster ones. Along with pairs of Atlas 0-8-0's, Trix F-9's (nice locos), Rapido GP7/9's (Fast as some slot cars!), and the PA-1's. Along with an assortment of crappy running Lima locos (4 or 5), Con Cor Pacifics (two, both ran badly), and a few others that I can't remember. Anything even close in speed I could run on a big train without any problems. I had twin mains, so speed comparisons were a cinch. Nothing I had came close to the Rapido (well named) Geeps, they would go so fast they would fly (not an exaggeration!) off the track on even my outside curves at anything over 3/4 throttle. Most of the rest of them, except a couple of the Lima locos, would stay on at full throttle. I was a fanatic about smooth trackwork. Almost all joints were soldered and smooth as glass. I made sure all my cars and locos were gauged correctly as soon as I took them out of the boxes. Derailments were a rarity, usually the cause of them was switchpoints sticking and picking a wheel. If it was an engine that hit it, and it was running a huge train, the cars behind the locos went everywhere. It was impressive, and I have to admit, worth the minor damage that resulted from all the slamming of cars into each other.

BDK

The only time I actually noticed wheelspin is if I put my Rapido Geeps on the front of a train with some of my slowest locos behind them. They would spin at the start, but after the train was moving at a decent speed, they stopped, or at least I couldn't hear them. The Geeps couldn't pull worth a damn out of the box, but after I added every bit of weight I could jam into them, they pulled ok. But they still were insanely fast. Even without a train on them, just "goosing" the throttle broke the wheels loose until I added weight.

BDK

BDK wrote in news: snipped-for-privacy@news.buckeye-express.com:

Long train runners sure do get wrecks to talk about. In my Ntrak club, we had a fellow running 60-70 Triple Crown road railers that derailed. Very realistic... All 3 mains got shut down, and while most cars stayed close to the centerline of the track, they still "slinkied" all over.

Puckdropper

I had a bunch of 50' boxcars and hoppers, and they would zig-zag all over the place in a nice realistic way when it went bad. The only slightly "wreck happy" cars I had were Gons when they had no weight added out of the box. After they got weighted down, they were ok, but still not the most stable. I almost always ran them at the end, just in case.

I did have a very poor quality 8MM movie clip of a huge train coming off the tracks due to it being thrown into "emergency". I had a transistorized throttle that when the brake lever was put into emer, it really slowed the locos down in a hurry, and the train slammed into them very much like a real train does. I loved that throttle, once a local electronics whiz upgraded it so it didn't self destruct when running one loco. It cost me almost as much as it did new to fix it. When it was done, it could run 5 locos without a problem, popping the breaker on my power supply instead. Acceleration effects were almost perfect. Sadly, it got popped when my TV antenna was hit by lightning. I had a hunk of coax running to the basement TV, and the coax was smoked, the TV was fine somehow, but the throttle and power supply were dead. The transformer on the PS was open, and the throttle had several scortch marks on the PC boards, so I sold it to a friend, for him to use for parts in case the case and panel got nasty looking with age.

His upgraded throttles survived to DCC when they finally got retired, almost 30 years.

BDK