Heljan slow speed performance

[JohnH]

I've got 5 x 26's, 2 x 27's and 2 x 47's (all Heljan)  Each one of them exhibits poor slow speed performance, when compared to my 2 Bachmann 25's, 24 and 2 x 20's which run like Swiss watches. My Hornby 50's and 31's will crawl along at such a slow speed without any problems too.

 

I'm going to try the less friction route on a 26 to see if that helps matters. Thanks for all the tips on here

[34theletterbetweenB&D]

 ...When comparing locos, I noticed that the Bachmann 20 motor will fit in to the Heljan 26 body cradle.  Got it in fine.  To my surprise, the 26 then ran worse than with the Heljan motor...

 Not in the least surprised.

 

The Bachmann motor used in their centre motor twin bogie mechanisms appears unchanged since the first example I looked at in about 1994, from the Peak; although I have not had one out of any model more recent than a 2010 or thereabouts production of the class 25 mech. Tested on the bench it, starts on very little current, has plenty of torque and is slightly 'rattly'. It is more than adequate in Bachmann's drive line design in my experience, yet to see a bad one among 20 purchased for my own use, and some number greater than that decoder fitted or otherwise tinkered with for friends, all could be got to start and run smoothly and pull well. The three significant running problems I have had to fix, it has been tightness in gear towers every time, the motors were fine. (The 'not running' problems I have seen were our old friend, drive coupler loose in the flywheel.) Small sample, other defects are possible, etc.

 

The Heljan motor used in their larger models is a very sweet running item based on the smaller sample I have had on the bench. Only recently had one out of the MLV, and it is a fine unit, very quiet and well balanced with monster torque for a small motor. Same external dimensions as the couple of much earlier motors I have looked at which were Buhler products; this latest one anonymous as to maker with 'E356A 1490' on the motor can. A rose by any other name and all that, it does the business.

 

My experience from the 47 and other early productions from Heljan was of their 'no coasting' characteristic, despite much the same flywheel mass as that on comparable products by Bachmann, Hornby, and HO manufacturers serving the American market. It was tightness in the gear towers every time. Free that up, and bingo, smooth starts and stops and free running resulted. Happily - based on my limited experience - the more recent products come with free running gear towers and have all performed near ideally from the box (2 examples each of class 15 and class 23, a 26/0 and most recently the MLV) starting very smoothly on plain DC, coasting to a halt and quiet at any speed.

 

Clearly this isn't universal experience of Heljan's product, but if wishing to assess for a DIY improvement to running, I'd have the mechanism apart and assess the motor and gear towers independently. I would be confident that the potential for smooth running is present in the design, it just needs elimination of whatever factor(s) in the assembly are interfering with that potential. The alternative as always is return to retailer as unsatisfactory; if my experience is anything to go by there are 'good ones' out there and a different unit is likely to perform well from the box.

[John Tomlinson]

I run old plain DC.  I have a couple of Bachmann 20s and 25s to compare against Heljan Class 26s and a Hymek.  All the locos are fine without a load.  With a load Bachmann locos are more more smooth and easier to control at starting smoothly than the Heljans.  My newest Heljan 26 being the worst (it has had plenty of running in time).  When comparing locos, I noticed that the Bachmann 20 motor will fit in to the Heljan 26 body cradle.  Got it in fine.  To my surprise, the 26 then ran worse than with the Heljan motor.  As per other people's advise, I therefore suspect there is more friction in the Heljan gearing which, although overcome smoothly when running light, with a moderate load in tow leads to that awful looking jump in starting.  I shall probably try and take apart the bogie towers to see if any improvements can be made. 

You may well be onto something here.

 

The thickness of the grease used as a gearbox lubricant by Heljan has been questioned before. My own experiences of dismantling a Clayton gave much improved performance after the white goo had been removed, and milder lubricant used in its place.

 

To be fair to Heljan, I suspect that all the gearbox greases tend to thicken with age. A little while ago I dismantled a Bachmann 42 Warship that was probably over 15 years old and cleared out the grease, again it then ran beautifully. I'm on good old DC as well!

 

John.

[Gwiwer]

See also my post made seven years ago on page 1 which notes that Heljan locos may suffer from contact wipers not making contact (all or some of the time) and a need to keep everything spotless.

 

Bachmann locos are more tolerant of small amounts of crud and Hornby will seemingly run no matter what though locos fitted with head and tail lights might flash both on dirty rails / with dirty wheels.  I put it all down to the need that Heljan power nit has for more current than its cousins.

 

On DC I have recently managed to get two class 33s to run sweetly double-heading an 11-coach train with beautifully smooth starts and realistic stops but a slow top speed due to the power required slightly exceeding that available.

[liathach]

Further to my earlier posts, I have finally hit on a solution which works for me.  I had tested (as per an earlier post) running the Heljan Class 26 with drive to one bogie one.  This did seem to give smoother running but at the expense of a big loss of traction.  I worked for a long time on clearing any tight spots in each tower in the hope that this would allow for smoother running with both bogies driving: no real difference.  I also tested with the lights disconnected (slightly less power needed to start).  I tested with drive to three, rather than four axles (still not great).  In the end, I opted to have drive to just the end most axles which are just one cog away from the worm drive.  This made an extraordinary difference to having consistent, easy to control starting with a load.  For comparison I did the reverse and connected up just the axles on the inside of each bogie: due to the transmission through the multiple cogs in each tower, it was back to square one!  Back to having just the outer axles powered, the only downside is that you lose the ability to haul big loads.  I have put some additional weighting in to the loco to assist.  I have tested this on another of the class 26's and again it has made a huge improvement to smooth, consistent starting with a load. Thus, rather than have drive to one bogie only, I recommend you try disconnecting both inner bogies from the drive and then adding weights to assist with haulage.