TRAIN SPEEDS

I would like to thank you for being so friendly on the BRM stand in London, and answering so many of my questions. But I have one more...

Trains run well on my track, but then slow after passing a point. From there, the train continues straight and continues slowly until a section of track before another point, where it returns to the main line again, only to return to normal speed. If the train turns off at the point and re-joins at the other point, no speed is lost. The track wiring is outside of this section. Any tips would be great.

Trevor (Sweden)

Howard Smith says…

It sounds like your train is experiencing some form of resistance, be it electrical, or mechanical, though most-likely the former. Is this a DC or DCC layout? Copper wires conduct electricity better than rail, and longer lengths of rail increase resistance. I’d advise soldering a dropper wire to each rail and connecting it to a common bus wire (check the gauge of the wire used, too!), which can carry sufficient amperage. If you’re controlling the layout using a DCC system, for longer sections of track, segmenting the layout into ‘zones’ with booster units is good practice. Never rely solely on point blades making contact with the outer rails for electrical continuity.

With this done, and, assuming you have no short circuit – test with a multimeter – for layouts with tight radii, mechanical rolling resistance is worth considering, too, and locomotives can be affected by small radius curves. The issue can be exacerbated for locomotives with a high axle count, where wheel flanges are more prone to push against the rail sides, increasing resistance. As axles are displaced to conform to track curvature, the rear of the wheels can be pressed into sprung pick-ups, again, impacting performance through increased resistance. Longer trains around curved track increase rolling resistance, too.

In summary, a little mechanical slowing of trains around curves is to be expected, but it sounds like an electrical problem at fault here, so a resistance test, rail breaks, and dropper wires should cure the problem.