BLI PRR-P5A In Now

[narrowminded]

I assume it wouldn't be any problem for them to mass-produce your parts, so the next run should have them factory-installed.

They would be welcome to it!  Even as an easy fix for the ones already out there. 

I could see several ways that the problem could be addressed in production.  I actually do like the idea of supporting the truck arm as that part does and in production I suspect that feature could be incorporated into existing parts.

[motofavorite]

Then I look at those solid non-see-thru drivers and Ugh... it looks like
an American Flyer engine.  Why do they keep clinging to solid drivers?

That annoys me to no end. I remember that the drivers on my Rivarossi heavy pacific were made from a fragile compressed paper product. I could not say today whether that technology permitted see-through drivers. But those spokes sure were more impressive to me than BLI's drivers.

[peteski]

That annoys me to no end. I remember that the drivers on my Rivarossi heavy pacific were made from a fragile compressed paper product. I could not say today whether that technology permitted see-through drivers. But those spokes sure were more impressive to me than BLI's drivers.

This photo is already dated. Point is that see-through drivers have been around for very long time, and that solid drivers don't look very realistic.

[dem34]

That's good news.   And assembly was clear and easy?

Less than five minutes lol.

[narrowminded]

I just received my second P5a!  I really like these things and now that I'm confident that they can run reliably I found I needed a second one and may still need a freight unit or two or...   

This was also an opportunity to review this fix with a brand new unit without any incremental changes as the performance issues were being worked out.  The unit is factory new, opened the box in the exact same fashion as anyone receiving one.  First, I checked the weight being applied at the trucks using my gram scale fixture that was seen in a prior video.  That resulted in 3.4 grams at the traction tire end and 3.6 grams at the metal drive wheel end.  That's in line with what I had seen in my first one with the factory springs. 

I then placed the unit on my layout.  It had the previously experienced power dropouts but would complete laps, even with hiccups, at speed step 30 or above (Digitrax DT-402D and DB 150).  As soon as I dropped it to step 20 or less it had dropouts or stalls, not making a complete circuit without such an event.  And don't even bother with speed step five or less.  Repeated dropouts and stalls.    

The next move was to clean the wheels.  New parts with the potential for plating, parts washing, and general new part processing residue can be suspect and experience tells us this.  The way I cleaned the wheels was one wheel at a time with a toothpick, alcohol, and a wiping towel to clean the toothpick as dirt appeared on it.  On some wheels the toothpick dirt buildup was greater than others but on none did I feel I was wasting my time.  The toothpick is tedious but worth it as it's not needed often.  The toothpick was soaked in the alcohol with a very small amount dispensed in a shot glass, my small parts wash tub.      The metal drive wheels (not traction tires) are also part of the pickup scheme so they were cleaned by connecting jumper wires to a truck wheel set and to the layout rails.  The same alcohol and toothpick procedure was used here.  Next run, better but not reliable and still very troublesome at speed step five or less.

Finally, installed the truck support pieces.  The same support pieces I've sent out to a lot of P5a owners.  The gram scale check showed the traction tire end at 26.8 grams and 23.8 grams on the opposite.  It has about 3 hours run time now at speed step one, not a hiccup yet, so I'm shutting it down until I can actually play .  That's the point of this whole effort.   Your results may should not vary.

[bbussey]

I’m not having the best of luck. I replaced the springs and added the new support pieces before swapping out the center driver and traction tire driver. The center driver isn’t interchangeable unfortunately, as the center gear has to be aligned perfectly to interact with the driver gear. Also unfortunately, I haven’t been able to get everything realigned properly. The good news is that the electrical pickup issues are resolved. It definitely responds at the first speed notch with no power dropout. The bad news is now I have gear integration issues. The motor is spinning but no movement. Since I’m now having center driver issues, I’m going to take the opportunity to swap flanged wheels onto the center driver axle.

Also, on my unit, the outer drivers were in the reverse orientation of the center driver. On all the drivers, one wheel is spoked and the other has extra detail between the spokes. I’m curious if everyone’s units have the same driver orientation.

[narrowminded]

I’m not having the best of luck. I replaced the springs and added the new support pieces before swapping out the center driver and traction tire driver. The center driver isn’t interchangeable unfortunately, as the center gear has to be aligned perfectly to interact with the driver gear. Also unfortunately, I haven’t been able to get everything realigned properly. The good news is that the electrical pickup issues are resolved. It definitely responds at the first speed notch with no power dropout. The bad news is now I have gear integration issues. The motor is spinning but no movement. Since I’m now having center driver issues, I’m going to take the opportunity to swap flanged wheels onto the center driver axle.

Sorry to hear the gear issues.    Glad to hear the pickup's good.

Also, on my unit, the outer drivers were in the reverse orientation of the center driver. On all the drivers, one wheel is spoked and the other has extra detail between the spokes. I’m curious if everyone’s units have the same driver orientation.

My new one is the same.  On my old one they are all matched.   We'll have to learn which way they should be.  My guess would be all the same but I don't even know what or why the difference.   One thing I did just discover on my new one is that one end has the air hose details in the vicinity of the coupler not fully seated and is interfering with the coupler swing in that direction.  It's staying coupled and hasn't derailed anything on the curves yet but it isn't really correct.  I'll mess with it later.

[peteski]

I’m not having the best of luck. I replaced the springs and added the new support pieces before swapping out the center driver and traction tire driver. The center driver isn’t interchangeable unfortunately, as the center gear has to be aligned perfectly to interact with the driver gear. Also unfortunately, I haven’t been able to get everything realigned properly. The good news is that the electrical pickup issues are resolved. It definitely responds at the first speed notch with no power dropout. The bad news is now I have gear integration issues. The motor is spinning but no movement. Since I’m now having center driver issues, I’m going to take the opportunity to swap flanged wheels onto the center driver axle.

Also, on my unit, the outer drivers were in the reverse orientation of the center driver. On all the drivers, one wheel is spoked and the other has extra detail between the spokes. I’m curious if everyone’s units have the same driver orientation.

Interesting about the touchy gear alignment.  I might be able to get my hands on one of these models in the future. I'm curious to see how it is designed.

As far as those wheel details go (those "things" between spokes on one side are depicting the quill drive coupling of the motor to the wheel), if you zoom in on the wheels in the parts diagram PDF, you will see that it shows the center wheel flipped 180 degrees from the outer drivers. Seems that is done on purpose. Also there seem to be indication of flange on the center driver (which in not on the model).

[narrowminded]

Interesting about the touchy gear alignment.  I might be able to get my hands on one of these models in the future. I'm curious to see how it is designed.

As far as those wheel details go (those "things" between spokes on one side are depicting the quill drive coupling of the motor to the wheel), if you zoom in on the wheels in the parts diagram PDF, you will see that it shows the center wheel flipped 180 degrees from the outer drivers. Seems that is done on purpose. Also there seem to be indication of flange on the center driver (which in not on the model).

Seems I'll be flipping some wheels.  But which ones?

That gear gear end play is interesting.  The two end axles have a decent amount of side play in them and the center has a minimal amount and it's that way on purpose.  The center bearings have an extra boss on them that takes that play out and the end two don't have that, allowing them to float side to side.  It would seem that they might have originally planned on all three drivers flanged and the end play in the outer two axles would be to allow the axles to shift as needed in curves.  But the center is now flangeless, still with minimal play.  Maybe it's to do with worm alignment above that center gear.

If necessary a Delrin spacer/ thrust ring could be machined that would snap over the axles between the wheel back and the bearing flange to keep them more centered.  The snap over feature would save having to mess with pressing wheels on and off and the problems that invites, as well as re-gauging.  Because the center wheel is flangeless, making it effectively a four wheel chassis, they don't need to float like they might if the center wheels were flanged.  And if you add flanged center wheels you may appreciate that outboard axle end play.

[peteski]

Seems I'll be flipping some wheels.  But which ones?

Since the chassis is asymmetrical and present in the drawing, to me the driver orientation is not ambiguous.

[bbussey]

Okay, I finally got everything working.  I believe the problem was that I had the gear cover on backwards, which was forcing the gears to offset slightly to the opposite side.

I pulled the blind wheels off the center axle, cut bushings from brass tubing to match the thickness of the extended bushing on the blind wheels, then added them to the axle and pushed on a set of flanged wheels that I pulled from one of the standard driver sets that BLI sent (making sure that the new quill wheel was on the same side as the blind quill wheel.  Then, I replaced the traction tire driver with the second standard driver set I got from BLI.  I made sure the quill detail on both outer drivers was the opposite of the center driver.

When I installed the "standard" gray set of Mark's correction support pieces in my first attempt, it seemed excessive with the traction tire gone.  The gears were spinning then but I was getting major slippage.  So I used instead the clear correction support pieces that were designed for trucks with stretched springs.  That must have been when I flipped the gear cover, because it stopped moving after the second disassembly.  But now is working perfectly.  Speed notch one and no power interruptions, and all 14 wheels are both touching the rails and conducting.

All that is left to do now is adjust the volume on some of the sounds and alter the headlight programming so that the front headlight stays on regardless of travel direction.  Great job on the fix Mark, it's a night and day difference.

[bbussey]

That gear gear end play is interesting.  The two end axles have a decent amount of side play in them and the center has a minimal amount and it's that way on purpose.  The center bearings have an extra boss on them that takes that play out and the end two don't have that, allowing them to float side to side.  It would seem that they might have originally planned on all three drivers flanged and the end play in the outer two axles would be to allow the axles to shift as needed in curves.  But the center is now flangeless, still with minimal play.  Maybe it's to do with worm alignment above that center gear.

If necessary a Delrin spacer/ thrust ring could be machined that would snap over the axles between the wheel back and the bearing flange to keep them more centered.  The snap over feature would save having to mess with pressing wheels on and off and the problems that invites, as well as re-gauging.  Because the center wheel is flangeless, making it effectively a four wheel chassis, they don't need to float like they might if the center wheels were flanged.  And if you add flanged center wheels you may appreciate that outboard axle end play.

The lack of play in the center driver definitely has to do with keeping the driver in line with the worm gear.  There is no margin for error in the alignment it seems.  Now that I have flanges on the center drivers, I'm not going to worry about the float in the outer drivers as it's not excessive and probably is a benefit while transitioning into curved trackage.

[narrowminded]

Okay, I finally got everything working.  I believe the problem was that I had the gear cover on backwards, which was forcing the gears to offset slightly to the opposite side.

I pulled the blind wheels off the center axle, cut bushings from brass tubing to match the thickness of the extended bushing on the blind wheels, then added them to the axle and pushed on a set of flanged wheels that I pulled from one of the standard driver sets that BLI sent (making sure that the new quill wheel was on the same side as the blind quill wheel.  Then, I replaced the traction tire driver with the second standard driver set I got from BLI.  I made sure the quill detail on both outer drivers was the opposite of the center driver.

When I installed the "standard" gray set of Mark's correction support pieces in my first attempt, it seemed excessive with the traction tire gone.  The gears were spinning then but I was getting major slippage.  So I used instead the clear correction support pieces that were designed for trucks with stretched springs.  That must have been when I flipped the gear cover, because it stopped moving after the second disassembly.  But now is working perfectly.  Speed notch one and no power interruptions, and all 14 wheels are both touching the rails and conducting.

All that is left to do now is adjust the volume on some of the sounds and alter the headlight programming so that the front headlight stays on regardless of travel direction.  Great job on the fix Mark, it's a night and day difference.

Glad to hear you got it working.  And your experience with the spacer bars makes perfect sense with your all metal drive wheels.  The gray pieces that I list as the fix with the factory springs do what they were supposed to and are actually higher than the clear parts that you (and I) used with the stretched springs.  Well, every bit of weight that is transferred to the trucks is taken away from the drive wheels and now that yours are all metal they really needed the extra weight on the drive wheels.  That doesn't help as much with the truck pickup but you've added another set of conducting drive wheels that you didn't have before.  I think there's a little bit of pickup juggling going on there but probably nets out about the same. 

The one thing I would worry about is that these things are basically a four wheel drive loco, at least at some point with even minor track fluctuations, and as such, I can't imagine it pulling much at all without the traction tires.  They are pretty heavy but I doubt they're heavy enough to pull much more than their own weight with just metal to metal wheels.  I'd be curious to hear how that works out.

And did the flanged wheel take up the original center wheel to track clearance?

[peteski]

The lack of play in the center driver definitely has to do with keeping the driver in line with the worm gear.  There is no margin for error in the alignment it seems.  Now that I have flanges on the center drivers, I'm not going to worry about the float in the outer drivers as it's not excessive and probably is a benefit while transitioning into curved trackage.

Most N scale locos with long rigid frame are designed to allow some lateral play in some axles, for the reason you mentioned.    The N scale curves are so much tighter than prototype that the lateral play is needed for the loco with rigid frame to be able to freely traverse the curves.   This can be clearly observed in most long frame steam locos.

[bbussey]

The one thing I would worry about is that these things are basically a four wheel drive loco, at least at some point with even minor track fluctuations, and as such, I can't imagine it pulling much at all without the traction tires.  They are pretty heavy but I doubt they're heavy enough to pull much more than their own weight with just metal to metal wheels.  I'd be curious to hear how that works out.

And did the flanged wheel take up the original center wheel to track clearance?

The prototype couldn’t pull either, which is why it was doubled and tripled up. So I have no problem that the pulling power is reduced. If I was a Pennsy modeler, I would buy another one or two units to MU. I may end up buying a second unit and modifying it if the one unit ends up being a pulling dog, but for now one unit is good.

Yes, the center driver wheels are now touching the rails, and the center driver is the lone driver directly driven by the worm gear. The center driver in turn drives the outer drivers. So now, not only do I now have 14-wheel pickup, I also now have six drive wheels as opposed to four drive wheels with two traction tires. It should pull sufficiently with the extra set of wheels.