Every rail joint must be carefully aligned, properly fitted, and level. Sight along the rail to check the alignment through the rail joiner. After the track is spiked down, use a fine file to smooth the top and inside corner of the rail joint until you can slide a fingernail across it.
Turnouts, or track switches, are the most common places where derailments occur due to the many interruptions in the rails. Gauge is critical at the switchpoints, rail joints, and the frog assembly, and anything which impedes the smooth passage of the wheels is a potential problem. Tight track gauge squeezes the flanges against the railheads and makes the wheels climb up and derail. Wide gauge also causes problems as the backs of the wheel flanges cannot span the space between the guardrail and the frog, forcing the wheelset to climb up and create another potential derailment. Commercial turnouts tend to be a bit wide at the frog. This can be corrected by filing the inside faces of the guardrail and the frog until the gauge pins fit properly. I also sharpen the point of the frog at this time. Gauge can be adjusted on turnouts with plastic ties by gently heating the outer rail with a soldering gun, pushing the rail into gauge, and then allowing the ties to cool.
The movable switchpoints must be tapered to fit tightly against the stock rails and provide a smooth passage for the wheels. Commercial switchpoints often have blunt ends which catch the wheel flanges and cause derailment. Use a file to blend the top edge of the point into a smooth transition. If you can slide a fingernail over this transition without it snagging, the wheels will also pass easilv. Check the gauge across both switchpoints as sorne are thicker than others. This means the turnout can be in gauge when it’s lined for one route, but off in the other direction. File material off the inside of the thicker point to correct the gauge.
Install couplers properly
Couplers take a surprising amount of mechanical abuse on a layout, so their operating reliability depends upon proper installation and regular maintenance. Read and follow the manufacturer’s instructions and take time to adjust the couplers for proper centering and minimal vertical play. Inspect the coupler and its mounting parts closely before installation and carefully remove any molding flash which impairs free movement.
Next, make sure the coupler box cover and its mounting screw(s) or the metal retainer clip are properly seated.
Finally, place the car on a piece of track and check the coupler height. Kadee makes an excellent HO gauge for this purpose; Micro-Trains makes one for N. Most freight cars tend to be low, so use washers to adjust the height for a perfect vertical match.
Most freight cars need some additional weight to obtain the best performance. The NMRA’s Recommended Practice 20.1 includes the following formulas to determine the optimum weight based on the different car lengths (in inches):
Recommended total car weight (in ounces)
- O scale: 5 plus 1 ounce per inch of length
- S scale: 2 plus 1/2 ounce per inch of length
- HO scale: 1 plus 1/2 ounce per inch of length
- N scale: 1/2 plus .15 ounce per inch of length
All weight should be kept as low in the carbody as possible and the weights should be centered and secured so they cannot slide out of position and make the carbody tip to one side.
Check and adjust wheelsets
Wheelsets that are in gauge and centered on the axles are essential. I check every wheelset on every piece of equipment before it goes on the railroad. Most model manufacturers work to reasonable tolerances, but variations in gauge do occur. Two notches on the side of the NMRA gauge make it easy to check this dimension.
Wheelsets that are out of gauge can generally be adjusted by twisting a wheel along the axle until they match the gauge. Just be careful to keep the pair of wheels centered on the axle or you’ll wind up with a dogleg truck, where both axles may be in gauge, but the truck’s angled tracking forces the flanges into the rails making them very prone to derailment.
Inspect the trucks carefully and make sure all of the wheels contact the rails with even pressure. Cast, rigid truck frames sometimes warp slightly during shipment or storage. If so, they can be warmed under hot tap water and gently twisted until they’re square again. If sprung trucks do not equalize smoothly, look for casting flash on the moving parts and carefully remove it.
Adjust truck mounting
The trucks should be mounted on the car so they swivel freely. Any stiffness here forces the wheel flanges into the railheads; where they’ll find any imperfection. Both trucks must rock a little under the carbody to handle slight irregularities in the track.
I’ve also found that one truck can be kept fairly tight to keep the carbody from wobbling from side to side, but then it’s essential to leave the other truck fairly loose.
Use minimum lubrication
Couplers should be lubricated with powdered graphite Teflon as those don’t attract dirt. A little puff of lubricant does the job and lasts a long time.
Needlepoint wheelsets running in acetal plastic sideframes seldom need lubrication unless they make noise. In such cases a puff of powdered Teflon does the job. Oil isn’t recommended as it dries out and turns to a gummy residue that adds a lot of drag. Some petroleum-based oils will also damage the plastic in the sideframe.
Brass or metal trucks get a drop of light oil only if they make noise (the squeaky wheel gets the oil). Overlubrication seeps out and may damage the paint job.
Make running repairs
Everything I’ve covered so far can be done as you build your equipment fleet. But what about the cars already on the layout? A hard-nosed inspection of every car about once a year will reveal all sorts of things that have changed due to the wear and tear of an operating layout. The last time I did this major inspection only about ten percent of my veteran cars passed all of the standards!
To repair the numerous bad order cars (a prototype term for cars needing repairs), I sort them by the degree of work required. You’ll find most require only minor repairs like adjusting the couplers, loosening a truck screw, or adding a bit of lubricant.
Maintain the fleet
Many experienced modelers remain willing to put up with derailments as the price of running trains, but that’s a rationalization to avoid investing the time it takes to make the necessary adjustments. Observe what’s happening as the trains run and be hard-nosed about taking care of problems as soon as they’re identified. After a while, you’ll find fewer problems which need attention.
With the quality of the equipment we have today, there’s no reason to put up with derailments any more. Putting in the five or ten minutes required to eliminate specific track problems, change-out bad wheelsets, and adjust each car makes an amazing difference in how your railroad performs – even when visitors are present.