Athearn PA-1 wheelbase of the bogies?

[richierich]

Just a question regarding the wheel base of the bogies on the Athearn PA-1 loco?

 

I’m wondering what this is and how well it would match up with a Lima Class 31 bogie wheel base.

 

I suspect it’s about 2mm too short. But that is based on scale calculations from the full size loco, rather than model.

[34theletterbetweenB&D]

That's a blast from the past! The HO PA1 mechanism was slightly short overall for an OO Brush 2: but the drive was so much better, and the bogie frames were a good approximation too.

 

A bit of scrounging around may still find you a s/h slightly mazak rotted Hornby mechanism. I have several such acquired as 'breakers for spares' and the deterioration of the cast block after the cab floors have dropped off has been very slow: and mechanically the good performance is unaffected, and they come with correct wheel diameters and bogie frames.

[richierich]

I have seen Hornby super detail Class 31s with the mazak issue on eBay, but these sell for quite high prices. I've got quite a few Lima 31s which could with a better drive system, hence looking at Athearn PA-1 as a possible source of parts.

 

I've also tried the Railroad motor bogie, but under DCC I cannot get satisfactory slow speed control, well not as a good as the original Lima motor! So not that impressed with railroad motor bogie.

[John ks]

Heres one I prepared earlier

 

About 40 years earlier

The DCC is a recent addition & the motor was replaced with a more recent Athearn version

It is basically an unmodified PA mechanism. The Triang/Hornby fuel tank was fitted over the Athearn casting with some cutting & filing. 

 

 

The class 47 is a more resent conversion using PA bogies, motor & drive with some milled parts to hold everything together

 

 

The cab interior and Hornby frame had to be modified to fit around the Athearn bogie

Led lights were added while I was at it

 

 

The Athearn wheel centres don't quite align with the side frames

 

 

from a normal viewing angle this is not very noticeable

 

The big disadvantage is that when running they sound like Athearn locos

 

John

 

 

 

 

[34theletterbetweenB&D]

I have seen Hornby super detail Class 31s with the mazak issue on eBay, but these sell for quite high prices. I've got quite a few Lima 31s which could with a better drive system, hence looking at Athearn PA-1 as a possible source of parts....

 The Athearn/Hornby price comparison would be interesting. Even if it is somewhat more for the Hornby you will not regret it, Quiet, smooth, pull side out of house traction; and of course the right wheelbase and bogie design thrown in.

 

 

...The big disadvantage is that when running they sound like Athearn locos...

 But not so bad as the Airfix motor bogies for the Brush 2. I had a pair of Brush 2s; one Athearn, one Airfix twin motor. The grindings added somewhat to the ensemble. Mind, I was running outdoors at the time.

 

There's another thought, if you can put up with the racket (!) the Airfix motor bogie is a very good unit with a Zimo decoder to beat it into submission.

[Satan's Goldfish]

Am I right in thinking you're referring to these for re-motoring Lima 31s?

 

https://www.ebay.co.uk/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=athearn+pa1&_sacat=0

 

Basically £40 for a pair of chassis... not bad! How do the wheels compare to the Lima pizza cutters? Are they code 75 friendly?

 

Ta

[Guest teacupteacup]

Am I right in thinking you're referring to these for re-motoring Lima 31s?

 

https://www.ebay.co.uk/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=athearn+pa1&_sacat=0

 

Basically £40 for a pair of chassis... not bad! How do the wheels compare to the Lima pizza cutters? Are they code 75 friendly?

 

Ta

The Athearn wheels have rather fine profile flanges, not sure if the older ones are to RP25 but better than Lima's!  Run perfectly on code 75 I've found

 

I file down the Lima flanges to make them run ok on code 75, with a bit of work the pancake motor can be made to run pretty smoothly, esp with DCC!  Sound like a bag of spanners at times though.

 

I've found the new Hornby Railroad motors to be ok, but much extra weight is needed to tame the gearing, and fiddled CVs help too.

[John ks]

A trap for the unweary

 

The early Athearn PA's have a metal sideframe which also contains the axle bearings, if you want change these for more accurate ones then it becomes a major job

 

The later versions went to an inside bearing & the sideframes are plastic & push into the side of the bogie, these sideframes are decorative & only go along for the ride

 

The D5572 in post 4 used the earlier bogies with metal sideframes

 

The class 47 uses the later bogies & has sideframes from the class 47 glued to the bogie(on appropriate spacers), unfortunately the axle spacing on the PA is slightly shorter than the Class 47   

 

John

 

PS Just to clarify the early Athearn had a very distinctive sound, whereas current Athearn are much quieter

[The Bigbee Line]

The proto 2000 is worth a look..

 

https://www.ebay.co.uk/itm/HO-Scale-Life-Like-LV-Lehigh-Valley-PA-1-Diesel-Locomotive-611-Powered-Model/332529295817?hash=item4d6c4a61c9:g:SmEAAOSwMqBaZllX

 

Smoother operation than the Athearn, even though the mechanism design is a clone.

 

Thanks

 

Ernie

[Guest teacupteacup]

The proto 2000 is worth a look..

 

https://www.ebay.co.uk/itm/HO-Scale-Life-Like-LV-Lehigh-Valley-PA-1-Diesel-Locomotive-611-Powered-Model/332529295817?hash=item4d6c4a61c9:g:SmEAAOSwMqBaZllX

 

Smoother operation than the Athearn, even though the mechanism design is a clone.

 

Thanks

 

Ernie

Agreed, only think to watch for is split gears.

 

Had a few over the years, run fantastic but can be affected by the gears.  If you go down that route, make sure you hear it run first.

[The Bigbee Line]

I have a stash of athearn gears that are a drop in replacement. Not expensive. An essential with any proto loco.

[richierich]

I'd reuse the Lima bogie frames, or at least the sides.

 

I did try a DCC decoder in lima 31, and slow speed performance was superior to a railroad bogie, which I'm not personally overly impressed with. The rail road motor bogie is geared for speed, and the motors seem to perform poorly, even under DCC. Lima has not so good slow speed performance because of the gearing for speed and three pole motor arrangement. With a 5 pole armature, which doesn't exist for a Lima motor, I think slow speed performance would be acceptable.

 

I have looked at the CD drive motor idea, but these motors aren't really design for variable speed.

 

But slow speed performance isn't as good as super detail Hornby 31. Can easily get a sleeper by sleeper crawl. But its unlikely I'd buy one to strip for the bogies and motor, unless its one with mazak pest.

 

People make out the super detail Hornby 31 body isn't right, but for me I like it, and I like the Lima body, especially without the prismatic glazing.

Edited January 27, 2018 by richierich

[Guest teacupteacup]

I'd reuse the Lima bogie frames, or at least the sides.

 

I did try a DCC decoder in lima 31, and slow speed performance was superior to a railroad bogie, which I'm not personally overly impressed with. The rail road motor bogie is geared for speed, and the motors seem to perform poorly, even under DCC. Lima has not so good slow speed performance because of the gearing for speed and three pole motor arrangement. With a 5 pole armature, which doesn't exist for a Lima motor, I think slow speed performance would be acceptable.

 

I have looked at the CD drive motor idea, but these motors aren't really design for variable speed.

 

But slow speed performance isn't as good as super detail Hornby 31. Can easily get a sleeper by sleeper crawl. But its unlikely I'd buy one to strip for the bogies and motor, unless its one with mazak pest.

 

People make out the super detail Hornby 31 body isn't right, but for me I like it, and I like the Lima body, especially without the prismatic glazing.

I tried one of the CD Motors (Modeltorque) I think it was.  Didnt make much difference I dont think, it was still way too fast and rather noisy too,

 

I found a video on youtube a few years back that took you through a step by step guide to thoroughly stripping down the Lima motor, smoothing off the gear wheels and re-assembly.  Its worth spending that bit of time doing this whether you're DCC or not.  The only Hornby Railroad motor I've came across that was good out of the box was in a 47, nice slow speed control and even better when a chip was installed.

 

The Railroad 31 is a mix between refurbished and non-refurbished shells - non-refurbished bodysides and roof with refurbished cab fronts (noticable with the bodyside waist height banding).  I do like the Lima shell though, been a firm favourite of mine for many a year