This is a topic I see referred to regularly both here and in 'the other place'. Such comments as 'I have just built a Langley Prince and need to fit pickups to the tender so it will run through Peco points without stalling' seem to be relatively commonplace. The responses usually seem to include 'Make sure your track is scrupulously clean', 'avoid dead frog points' and 'Peco points made before.... don't work'. Now this post is not meant in any way to brag about the running qualities of my locos but rather to raise awareness of a couple of points (pun not intended) that seem to be overlooked.
A couple of weeks ago I attended the Thorncombe exhibition and spent some time operating (well, watching trains go round from behind the layout) Ed Florey's 'Tipyn O.Bopeth', built by Geoff Broadhurst. Behind the scenes the track is Peco N gauge setrack complete with eight dead frog points. Ed has lots of locos, mainly Roco and Kato derived but he also has one of my Dirty Doris Rustons, which, of course, like any proud father, I favoured for operating. Now these locos weigh next to nothing and have a wheelbase of 10.5mm. Yet the loco consistently negotiated the run of eight (four at each end of the rear loops) without stalling. And I like to run my locos slowly.
Why should it perform like this? Well, you may accept the scrupulously clean bit, for what it's worth I don't bother with this as I dislike the appearance of burnished rail surfaces, it makes it look even more oversize than it is, but each to his own. Whilst everyone cleans wheels every now and then, how often do they clean pickups? The contact between a pickup and a wheel is very small, even assuming the pickups are adjusted correctly and are making proper contact with the wheel. So contact is the first thing to look for. Then, check there is no detritus between the wheel and the pickup. It can be amazing how much dirt can collect in such a small space, which, of course, inhibits pickup. Lastly, remember if your chassis does not have pickups on both sides, the axle bearings form an essential part of the pickup chain. I know it is frowned upon in some, more exalted, circles, but my chassis are all live to track on one side. The two enemies to good running are dirt and friction and one lot of pickups creates half the friction of two lots of pickups. So, to get back to the original point, ensure that axle bearing are lubricated with a conductive oil.
If these steps are followed, I can't see why any additional pickups should be necessary. Virtually all of my locos are four wheeled, those that aren't have trailing trucks that do not collect current and I do not seem to experience pickup problems. Plus my track is not particularly well laid or level, I enjoy watching stock lurching prototypically through turnouts, nor is it particularly clean. But the pickups and axle bearings are.
Hopefully, food for thought.
Rod
A good point well made Rod.
I must admit to being guilty of cleaning track & wheels but giving the pick ups little thought ::)
Before any exhibition running I always check the locos to be taken to the show on my test track. If a loco runs poorly I check the wheels and pick-ups and often it is down to fluff collected on them. People on the viewing side of the layout often ask how do we get such smooth running. The reply is always the same, cleanliness of track, wheels and contact pick-ups.
Roger