How many cars can one PF motor actually pull?

[PaddMadd]

Hi everyone,

I'm fairly new to Lego trains, having bought my first one last week, with another one on the way. I'd like to build something longer than what I currently have, but I'm a bit curious as to how many cars a single motor can pull before the train gets too heavy. I know that most of the freight cars don't weigh much compared to the passenger cars, but I would love some input from some of the more experienced members here!

[Heppeng]

At a push on level track I have managed five, but to be on the safe side I don't go above four.

[Zerobricks]

I guess you are referring to a PF train motor? I guess you can tow much more with bigger wheels with rubber bands and L/XL motors. Also dont forget the heavier the loco, the more it can pull.

[Redimus]

It's a rather difficult question to answer, but with the provided traction tires, and the application of an old train weight brick as close to the motor as is possible (again to provide more traction), it has no problem reaching a decent speed with a couple of my (reasonably heavy moc coaches, and can happily pull (although not as quickly) 5 or 6 freight wagons (all default Lego designs and therefore relatively light), and that's on my less than level layout.

[dr_spock]

I managed 7 so far with my AEM7-AC engine on level track. The AAA battery box is right on top of the PF train motor. Mind you, HE set has shared Jacob boogies.

Edited September 1, 2014 by dr_spock

[zephyr1934]

It all depends on how heavy your cars are, e.g., you could probably pull 8+ flatcars with one train motor. On the other hand, two full horizon express sets (net of 6 cars/locomotive units) is probably too much for a single motor. Weight on the drivers also helps, but don't go too heavy. My rule of thumb is to try to use as many panels as possible on the cars and as many plates as possible on the locomotives. In most cases you can also put two motors on a single IR channel, but don't put anything demanding on the other channel.

[cgarison]

With one PF train motor, 5 brick built Lego train cars is the limit that I have found. I have pushed upwards to 6 in my experimentation, but found that the motor will time out in about 10 minutes of pulling.

[ust60]

Hello PaddMadd

not an easy question.

https://www.youtube....SRswo4A5ch_m5Uw

On my video channel are some videos. Perhaps answer your question yes a video.

Best regards Udo

[Chromeknight]

I have pulled train sets that are up to 15 cars long with one PF motor engine. The issue was then drag through curves not pulling power.

For completeness I should say my rolling stock is 16-long 2-axle light freight wagons (panelled box cars, open wagons and flats).

And the top speed was slowed with that many (which is prototypical anyway!)

I also had a loco with two PF motors. It could pull 6 7740-style 2-bogie 28-stud cars without breaking a sweat (or significant corner slowing)

[cgarison]

The issue was then drag through curves not pulling power.

Great observation and this is so true. Using the standard Lego curve at 180 degrees of turn and a short straight of track (4 standard Lego straigts), my limit is 5 cars with a single PF motor. If I were using the long arch curves on the PennLUG layout then I could pull 10 cars with the less effort than the short train on the tight turned track.

[andythenorth]

It absolutely depends on the wagon:

- 2-axle wagons with a long wheelbase have high flange-rail friction in curves, which creates significant rolling resistance.

- heavier wagons have higher rolling resistance, as you might expect.

- wheelsets make a difference, if they have collected fluff etc around the axle they have higher rolling resistance

It also depends on the engine:

- heavier engines have a higher tractive effort. On a level track, more weight in the engine is pretty much always good.

- two PF motors are roughly twice as powerful as one, give or take some electrical limits. But they will drain batteries twice as fast.

- for the last couple of years Lego have shipped a thick traction tyre on wheels which provides better tractive effort than those used on older wheels.

- the older RC trains used AA batteries which are heavier than the AAA in PF trains - more tractive effort, longer battery life.

- battery type matters a little: alkaline are typically 1.5v (6=9v), rechargeables typically 1.2v (6=7.2v), this makes less difference than weight in my experience though.

It also depends on the track:

- flex-track has high rolling resistance

- long or tight curves (180º), or s-curves sap torque (180º curves also increase chance of string-lining).

I have a dual-motored RC train which pulls 22 wagons around steep curves (180º with s-bends at entrance and exit). The cars are a mixture of 2 axle and 4 axle, all quite lightweight. I think a dual-motor PF engine would lift 40 or more lightweight wagons on straight track.

Edited September 1, 2014 by andythenorth

[BricksMcgee]

I'm fairly new to Lego trains, having bought my first one last week, with another one on the way. I'd like to build something longer than what I currently have, but I'm a bit curious as to how many cars a single motor can pull before the train gets too heavy. I know that most of the freight cars don't weigh much compared to the passenger cars, but I would love some input from some of the more experienced members here!

I think andythenorth has nailed it already, but here are my experiences:

One PF can pull a doubled-up Horizon Express (1 powered engine, 4 passenger cars, 1 dummy engine) no problem on level track. The red cargo train (3667) happily pulls 5 cars: adding a 6th car noticeably slows it down, especially around curves.

If you're after a bit more pull, try adding weights above the motor - might give you an extra carriage.

[andythenorth]

Got a video of the twin-motor RC train pulling around 22 wagons (didn't count closely). There is no extra weight in this engine, just 6 AA batteries. Uses the RC train motors which deliver about half the torque of the newer PF train motor.

See it here (flickr video is a bit unreliable, sorry in advance) https://flic.kr/p/p18pTj

Video is shaky - had an 18-month old child sat on my lap. I cut the video just before he sat down on the moving train. Big pile up, big tears.

Edited September 2, 2014 by andythenorth

[dr_spock]

I think andythenorth has nailed it already, but here are my experiences:

One PF can pull a doubled-up Horizon Express (1 powered engine, 4 passenger cars, 1 dummy engine) no problem on level track. The red cargo train (3667) happily pulls 5 cars: adding a 6th car noticeably slows it down, especially around curves.

If you're after a bit more pull, try adding weights above the motor - might give you an extra carriage.

I found adding boat weights over the PF motor in the Horizon Express reduces wheel slippage when pulling 4 cars plus dummy engine.

[Redimus]

I found adding boat weights over the PF motor in the Horizon Express reduces wheel slippage when pulling 4 cars plus dummy engine.

Yeah, I added a weight to the under frame detail of the yellow freight loco, and while not an ideal location compared to the motor, it has made a significant improvement to grip, especially on a layout where I tend to run 5-8 car fright trains and have a reasonable incline directly after a semi circle of standard radius curve.

[Hrw-Amen]

I have several engines with twin LEGO train (PF) motors and they will comfortably pull six passenger coaches that are 44X7 studs. They will not pull seven without wheel spin unless one of the passenger coaches also has a motor in it. I have a half brake/parcel coach with the motor in the brake/parcel section.

My single motored engines will just about pull three of them.

The single motored freight engines pull around 13 wagons that are 16X7 of various types and I have not yet reached a limit for what the twin motored ones or two links single motor engines will pull, but I have had them pull 22 wagons of that size before with no issues.

The only problem sometimes is the magnets give out but that is easily fixed with a 2x1 plate or tile. (As long as you are not shunting when it gets fiddly.)

As has been pointed out, if you use the wheels on the technique axles they will not pull as many as there is then more fricton to consider.

[juzo]

Already been said. I have several long freight trains. My Maersk with 2 motors can pull 2 engines and 6 flatbeds ok. Same with my 7939 cargo, it can pull up to 8 cars but i have 5 octans on that which are pretty light. I haven't ran my 9 volt stuff yet to test so will be interesting to see how it goes. BNSF with 5 double stacks and santa fe with 6 passenger cars, someone here may know on those.

[kibosh]

I have several engines with twin LEGO train (PF) motors and they will comfortably pull six passenger coaches that are 44X7 studs.

Already been said. I have several long freight trains. My Maersk with 2 motors can pull 2 engines and 6 flatbeds ok.

How are you guys controlling two motors? Do you just set them to the same channel? If so, do they seem to run the exact same speed? If not, I would assume one engine ends up getting pulled along by the other.

[Player]

Today I powered my double Horizon Express with 2 motors on one side. I was not impressed at all to say the least. Compared to my Emerald Night or Maersk train, the Horizon Epress was so gutless and slow, I immediately removed all power functions. I will never power it again, from now on it will just "sit on my tracks and look good". Hopefully a new train will soon be announced, so I can use my newly bought parts...

Edit; Nevermind.. I just modded my Metroliner with Club Car. It flies as a rocket and has these bright LEDs now. With minor changes, it's completely PF compatible.

Edited September 4, 2014 by Player

[PaddMadd]

Thanks for all the input!

My 60052 should be delivered some time today, so I'm going to experiment with different setups. I'm thinking that I'll try to run dual motors in one of the locomotives and see how it runs, as I noticed that my 3677 had some problems with pulling all 3 of it's cars after a few minutes. I'm also thinking of getting rid of my flex-track segments and getting standard rail segments instead, as I really didn't like the way my train behaved on them.

Another random question: I've noticed that a lot of train MOCers use the old 9V system with metal rails. Has anyone experimented with the newer PF/RC trains on these tracks? Would the newer wheels have more or less traction on metal rails than the plastic ones?

[ust60]

Hello PaddMadd,

if thou hast 9 volt rails from earlier days, you do not throw them in the garbage. The PF trains it should not matter whether they be in plastic or metal - rail driving. And you can use two systems in parallel (same time). Or you can use the electricity from the rail for PF trains and saves batteries.

https://www.flickr.c...08/14865271768/

https://www.flickr.c...08/14865235318/

Best regards Udo

Edited September 5, 2014 by ust60

[hoeij]

Today I powered my double Horizon Express with 2 motors on one side. I was not impressed at all to say the least. Compared to my Emerald Night or Maersk train, the Horizon Epress was so gutless and slow,

Mine runs fine, but I think the difference is not the train, it's the track. On a short oval it does not run well (and it doesn't look good either). On a longer track, consisting of much more straight pieces than curves, the train runs fine.

Shared bogies doesn't make the train easier to pull. What counts is the total weight of the train, and how many curves versus straights you have in the track (Horizon Express cars are heavier than the cars from most train sets).

[Chromeknight]

How are you guys controlling two motors? Do you just set them to the same channel? If so, do they seem to run the exact same speed? If not, I would assume one engine ends up getting pulled along by the other.

One receiver. Two motors.

One motor and a PF switch are connected to the same output of the receiver. The second motor is connected to the switch with the switch set so that the motors travel in the same direction on the track. The motors will run at the same speed.

Double motor engines are only really needed for stop/starts and curves. Along straights, a single motor engine will reach the same top speed under the same load.

[juzo]

One receiver. Two motors.

One motor and a PF switch are connected to the same output of the receiver. The second motor is connected to the switch with the switch set so that the motors travel in the same direction on the track. The motors will run at the same speed.

Double motor engines are only really needed for stop/starts and curves. Along straights, a single motor engine will reach the same top speed under the same load.

I do the same. Will be doing away with the switch soon and opening up one of the motors to alter the polarity so it runs in the same direction without the switch.

[kibosh]

Awesome! Thanks for the explanation.