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BLI UP 4-12-2

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  • Member since
    January 2005
  • 550 posts
BLI UP 4-12-2
Posted by hdtvnut on Friday, March 13, 2015 8:12 PM

If you are getting one of these, can you check to see whether the chuff is synchronized with the driver revolution?  You should hear a ONE-two-three ONE two-three cadence (three cylinder engine), but on two of ours locally, it does not match the driver worth a hoot.  I suspect the Paragon 2 was not designed to handle the unusual rate, and it is not adjustable.

Hal

 

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  • From: Dearborn Station
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Posted by richhotrain on Saturday, March 14, 2015 6:07 AM

I don't own the U.P. 4-12-2, so I cannot comment on the chuff rate.  But, I would be interested in the comments of those who own this locomotive regarding its overall performance.

Although it is fitted with a Paragon 2 sound system, it is actually a brass locomotive, part of the Brass Hybrid series.   It is not an articulated locomotive, so those 12 driver wheels are going to test tighter radius curves.  I cannot imagine great performance on my 32" radius curves.  I finally gave up and sold my BLI 2-10-2 and 2-10-4.

Rich

Alton Junction

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Posted by selector on Saturday, March 14, 2015 9:05 AM

My BLI ten-coupled locomotives worked fine on my 24" minimum radius last layout...no problems whatsoever.  They were intended to be low speed curves, and that was how I made the locos move through them.  Out on my mains, where curves were no less than 28", most above 36", I could run anything at high speeds.

I am awaiting my Hybrid UP 4-12-2.  If it's like other brass hybrids I own, it will be a keeper.  Very nice.

As a comment about this locomotive, it has two blind driver axles midway along the set of drivers.  This, plus generous lateral motion control, allows the Paragon 4-12-2 to negotiate 24" curves as a safe engineered minimum.  No need to make a goofy model with an articulated front.  Also, I believe the prototype had those blind drivers, and for the same reason they're needed on our models.

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Posted by richhotrain on Saturday, March 14, 2015 9:24 AM

selector

As a comment about this locomotive, it has two blind driver axles midway along the set of drivers.  This, plus generous lateral motion control, allows the Paragon 4-12-2 to negotiate 24" curves as a safe engineered minimum.  

I'll believe that only when I see it.  Maybe at a crawl, a 4-12-2 can take 24" curves without derailing.  But, my experience with the 2-10-2 and the 2-10-4 tell me differently.

Rich

Alton Junction

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Posted by selector on Saturday, March 14, 2015 7:02 PM

Rich, years back when our hosts tested the Paragon J1 2-10-4, they found that it would barely manage 21" curves if I recall, even though it was rated only for 22" curves.  I had mine around 22" curves on my first layout, but not at any great speed.  I also found, to my pleasant surprise, that I could get it to screech through a carefully laid 21" radius curve that I built expressly to try that loco out for myself based on MR's test result.  There was definitely some lifting of the odd axle.

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Posted by hdtvnut on Saturday, March 21, 2015 4:05 PM

Since spending some hours with my 4-12-2, and communicating with BLI, I can comment more.

The chuff cannot be synchronized with the driver revolution using the magnetic reed cam, as the gear ratio and the the divide-by capability of the decoder were not designed for a six-chuff scenario.  However,  BLI sez that by setting CV246 to 192, you can disengage the chuff switch from the decoder and set the chuff rate by adjusting CV233 (thus like most other decoders operated in the past-not accurate over much speed range).  I haven't tried it yet.

I also was having a problem with intermittant shorting.  This was the sixth driver touching something, probably the frame, at a certain angle and displacement.   An old BLI bugaboo.  I inserted a split KD gray washer between the right-hand sixth driver and the frame to fix.  When removing the driver set, found one of the springs was crushed down inside the frame.  It took some work to unkink it.

On my loco, F8 doesn't control the volume as indicated in the tech ref.  I only get two volume levels - full and very low.  I had to set CV134 down from 128 to get the master volume I wanted.

i need to play with both chuff and whistle.  The default chuff is shrill, and probably no fix for that.  But it also makes the volume louder for about a second every time the throttle is advanced even one step.  I don't like that as it sounds artificial.  The switch to a heavy-load chuff sounds odd, too; they are too different and the volume levels are wrong.  The whistle default is such that even a poke at the button gives a trailing quill.  A long press causes a quill lasting seconds after you let up.   I must see if I can set it for normal signaling.

The default speed curve is odd.  Nothing much happens until around step 70, where it suddenly starts speeding up at a faster rate.

The engine negotiated 28" radii on our club layout, but that was the tightest I had available for test.

This engine is very pretty.  My prototype expert says part of the frame that should hide the rear truck spring is missing, as well as a conduit over the top of the boiler, but overall I like it quite well.  I just need to fight with the decoder some more to suit my tastes.

Hal

 

 

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Posted by rrinker on Saturday, March 21, 2015 9:04 PM

 Key with no cam is to get it matched up at slow speeds where you can still see the drivers turn. At higher speed it makes little difference since you can;t see th position of the rods anyway. Even thr real thing, distinct individual chuffs pretty muc disappear at 20-25mph. Perhaps a bit higher on a large drivered passenger loco.

 I dunno, I have 2 steam locos with no cams or sensors, and as it slowly makes its way down the track, it's nicley in sync. By the time it gets out of sync, the drivers are turning too fast to see the individual rod position.

               --Randy


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

  • Member since
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Posted by selector on Sunday, March 22, 2015 12:21 PM

I don't know much about the Paragon series of decoders as I have only recently acquired a couple of them.  However, it seems as if they are meant to be set up much like the Tsunamis in terms of power sounds, acceleration, smoothening out the drive, etc.  I have one Tsunami-equipped older loco, I think a first generation Paragon J Class 4-8-4 of the Stealth (non-decodered) variety, and I got its drive silky smooth.  I only played with the sound of power CV's once, a few years back, and didn't like the result.  I also get that initial two chuffs or so loud and then the throttle sounds like it was pressed closed a bit and the sounds die off.

I believe the idea is that the decoder is supposed to measure BEMF and keep that power sound alive until the acceleration ceases.  In our models, they get up to speed when we impose a change rather quickly.  I would like it to be slower, and this is where CV3 may play a part...not sure.  I recall the manual for the Tsunami saying one CV that had to be set in this series controlled the duration of that power sound.  That one CV would be the first one to fiddle with.  Sorry, can no longer recall its number.

As for the chuff synch on this model, I watched a video taken and posted by a member in another forum.  The chuffs on his Paragon 4-12-2 were fast by about an 8th of a revolution of the main crank.  I asked if he was aware of a CV that could alter that rate, but he hasn't replied as of this morning.

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Posted by hdtvnut on Sunday, March 22, 2015 8:49 PM

There is no way to adjust the sync when using the cam because of the fixed mechanical ratio of the gearbox and electronic ratio of the input countdown of the decoder.  I believe they were designed for four chuffs with no thought of a six chuff engine.  The only thing that can be done to improve the appearance, confirmed by BLI, is to disconnect the cam with CV246, then adjust CV233 to the closest possible sync.  

Maybe I'll get a chance to take the shell off and measure the ratios.

Hal

 

 

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Posted by hdtvnut on Tuesday, March 24, 2015 2:42 AM

Sorry, I had the CV's reversed in the previous messages.  Now edited.  This procedure works to set the chuff rate as you wish.

Hal

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Posted by CAZEPHYR on Thursday, April 2, 2015 9:10 AM

hdtvnut

Sorry, I had the CV's reversed in the previous messages.  Now edited.  This procedure works to set the chuff rate as you wish.

Hal

 

Thanks Hal for all of your input on the 4-12-2 chuff sequences.  It is a nice looking loco and should be a very popular choice for steam fans.

CZ

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