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Question for train runners....do engines like the Emerald Knight run well???

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Question for those who like to run trains on their city layouts. How does the Emerald Knight perform?  Looking at YouTube not a lot of AFOL running this set or similar.

I moc'ed up a 75955 Harry Potter set with mixed results.  My moc has a powered tender.  On straight track runs great, get a "s" curve or switch and some derailments. Maybe one every 10th time thru a switch.  Basically the tender ends up pushing the engine up off the tracks.  Aware sets like the Emerald Knight use a powered engine and perhaps this problem is mitigated.   Concerned as at least on YouTube, AFOL typically are not running this train on their video's.  Assuming its performance related?

Looking for some guidance before getting to far down this road.  Will note, my passenger set 60197 (running two sets) works great and cannot recall my last derailment. One single power up motor more then enough to pull two trains.  My layout is very flat.

 

 

 

 

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Question for those who like to run trains on their city layouts. How does the Emerald Knight perform?  Looking at YouTube not a lot of AFOL running this set or similar.

I moc'ed up a 75955 Harry Potter set with mixed results.  My moc has a powered tender.  On straight track runs great, get a "s" curve or switch and some derailments. Maybe one every 10th time thru a switch.  Basically the tender ends up pushing the engine up off the tracks.  Aware sets like the Emerald Knight use a powered engine and perhaps this problem is mitigated.   Concerned as at least on YouTube, AFOL typically are not running this train on their video's.  Assuming its performance related?

Looking for some guidance before getting to far down this road.  Will note, my passenger set 60197 (running two sets) works great and cannot recall my last derailment. One single power up motor more then enough to pull two trains.  My layout is very flat.

 

 

 

 

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Posted (edited)

What derails on the loco first? The lead truck, or the driving wheels? Is this a modified HP loco set, or a MOC of your own (you said moc'ed up, so don't know which we're talking about)...?

Without knowing more details, the first thing that comes to mind is the lead bogie/truck. IRL, these have some lateral 'give' to them, but in order to simulate this in lego, most people double-articulate the connection between the bogie and the frame. Without double articulation, you will have issues in turns and S curves.

I cannot speak to the Emerald Night part, as I don't own one myself.

*edit* You do have the driving wheels arranged flanged-blind-flanged, right?

*edit 2* Another shot-in-the-dark is adding some weight to the loco to make it a bit more stable.

Overall, I don't like tender power, though it's basically a necessity with 6w trains. Lego brand HP locos are small and light, have a high center of gravity, and are easily derailed when pushed from behind through tight, stock Lego curves.

Edited by SteamSewnEmpire

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You have to modiefy the Emerald. There are several problems with that engine. In one of the Railbricks Magazine issues rhere is an article about the modifications.

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In general steam engines on R40 curves are tricky. If the drivers are unpowered, you probably want exactly one traction band on exactly one of the wheels. Any more than that and you will cause friction. Also, if you are using the small technic axle train wheels, typically Lego puts them on axle pins (one wheel per axle) if you put two wheels per axle be sure to remove the traction bands from these wheels. To be clear, any of the preceding is assuming the given axle is unpowered, any powered axle probably should have all of its traction bands.

The EN and the Croc both have internal gearing for the non-train motor. If you are not motorizing as designed, pull the crown gear from the driving axle to cut out the gear train. With all of the ball joints, the Croc is probably not a good engine for pushing.

Now on to your modified HP, it could be a couple of things. Pushing a locomotive from the tender is unstable by design, so if it can find bad track it will do its best to derail. Getting rid of the friction as per above will reduce the chance that the engine can then use the drag to derail. But you can also try to reproduce the problem at home. Build the geometry that was problematic at the show (S-curve, diverging switch, etc.) and put it in a small loop, make sure to have 2-6 straights before and after the feature if your show had the feature at the end of a long straight (a diverging switch right after a curve is a common problem for all trains, when possible put 1-2 straight segments between a curve and a switch). With your mini-layout run your train for a good long while to see if it derails at home too. If so, you know you've captured at least part of the problem and you can start looking closer to diagnose.

Now there are problems you will find at shows that you will not usually get at home, the most likely one in your case is sudden changes in elevation, e.g., your rail peaking or dipping due to uneven tables. I will use an 8 long technic axle under a rail joint to simulate bad tables

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Does your HP engine derail at a slower speed? 

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On 7/25/2020 at 10:55 PM, SteamSewnEmpire said:

What derails on the loco first? The lead truck, or the driving wheels? Drive Wheels

Is this a modified HP loco set, or a MOC of your own (you said moc'ed up, so don't know which we're talking about)...? Extended original engine by 4 studs.  Wheel configuration unchanged from original

Without knowing more details, the first thing that comes to mind is the lead bogie/truck. IRL, these have some lateral 'give' to them, but in order to simulate this in lego, most people double-articulate the connection between the bogie and the frame. Without double articulation, you will have issues in turns and S curves. My front bogie is as original set, 4 fixed wheels on the Technic swing arm.  

*edit* You do have the driving wheels arranged flanged-blind-flanged, right? Yes

*edit 2* Another shot-in-the-dark is adding some weight to the loco to make it a bit more stable. I added weight in the motorized tender to help with traction.  

Overall, I don't like tender power, though it's basically a necessity with 6w trains. Lego brand HP locos are small and light, have a high center of gravity, and are easily derailed when pushed from behind through tight, stock Lego curves.  Yes that is what I have happening.  As my engine takes a curve, the tender tends to push the engine up slightly and it leans with the curve, wheels come off the track slightly.  

Note: my comments to SteamStewEmpire questions are above in red.  Please read his original post earlier in this tread for his complete posting and thoughts.   

On 7/26/2020 at 1:44 PM, dr_spock said:

Does your HP engine derail at a slower speed? 

Cannot recall if speed matters for derailment frequency.  I want to say derailments are less common at slower speeds but that is just my impression, can run some tests next time running the engine.

 

On 7/26/2020 at 11:19 AM, zephyr1934 said:

In general steam engines on R40 curves are tricky. If the drivers are unpowered, you probably want exactly one traction band on exactly one of the wheels. Any more than that and you will cause friction. Also, if you are using the small technic axle train wheels, typically Lego puts them on axle pins (one wheel per axle) if you put two wheels per axle be sure to remove the traction bands from these wheels. To be clear, any of the preceding is assuming the given axle is unpowered, any powered axle probably should have all of its traction bands.

The EN and the Croc both have internal gearing for the non-train motor. If you are not motorizing as designed, pull the crown gear from the driving axle to cut out the gear train. With all of the ball joints, the Croc is probably not a good engine for pushing.

Now on to your modified HP, it could be a couple of things. Pushing a locomotive from the tender is unstable by design, so if it can find bad track it will do its best to derail. Getting rid of the friction as per above will reduce the chance that the engine can then use the drag to derail. But you can also try to reproduce the problem at home. Build the geometry that was problematic at the show (S-curve, diverging switch, etc.) and put it in a small loop, make sure to have 2-6 straights before and after the feature if your show had the feature at the end of a long straight (a diverging switch right after a curve is a common problem for all trains, when possible put 1-2 straight segments between a curve and a switch). With your mini-layout run your train for a good long while to see if it derails at home too. If so, you know you've captured at least part of the problem and you can start looking closer to diagnose.

Now there are problems you will find at shows that you will not usually get at home, the most likely one in your case is sudden changes in elevation, e.g., your rail peaking or dipping due to uneven tables. I will use an 8 long technic axle under a rail joint to simulate bad tables

Set did not have traction tires on engine main/drive wheels.  Did not add any.  Front bogie did include traction tires on all 4 wheels and left them on.

Bogie on Technic pins, spaced just enough to allow wheels to be mounted (4 stud spacing).  Pins are the short ones, one side the Technic cross, other the clip that fits inside a brick with a hole in it.

Engine is not powered, no gearing in engine.  All drive wheels (not powered) are on the small Technic pins, they all move independently.

Bogie is free to move side to side and slightly up and down with little effort.  One issue I have just found is that the drive rods will actual hit the bogie on a curve.  It hits in an area where the bogie is smooth and just stops the drive wheel for a second (its not powered so not a big deal)

  

 

49781800758_c8e7e3a4bc_w.jpgIMG_2587 by

49782340636_c6d8e5a6a0_w.jpgIMG_2588 by

 

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1 hour ago, dr_spock said:

Your engine's rear coupler looks like it is at its limits.

49782665057_6fa2d08a17_c.jpgIMG_2595 by Bill battles, on Flickr

Yeah, that's a huge problem. That, plus the tender pushing pretty much explains the derailments as far as I am concerned.

I wonder if it would be possible to fit one of the smaller motors in the HP loco? You'd obviously lose the cab in the process...

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Your engines rear coupler should be articulated ! So it follows the tender better. I typically make an up-side-down assembly with a technic liftarm and attach an old train magnet. 

If you browse my Flickr you can find some pictures.

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Let me look thru my spare parts for a option to revise the engine coupler.  Thank you for sharing your pictures as an example.

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