More About N scale
Note:
I declare my bias. I happen to be an "N scaler" and have been so continuously from the 1970s. I converted from my British-prototype layout when N scale was still very much in its infancy and Minitrix and early Arnold-Rapido locomotives were "state-of-the-art" little marvels of their day. I was attracted at that time to N scale, because I could not create credible scenery in 00, yet had difficulty with the slightly under-scale gauge appearance of 16.5 mm for the British prototype. (Oh yes, I knew about EM gauge, but did not have the confidence or inclination to get into it.)
The Emergence of N Scale:
When N Scale appeared, it endured the same sort of negativity as did H0 scale when it first replaced 0 scale as the predominant residential model railway scale. The arguments were along the same lines: "oh it's cute, but you need a jeweller's kit to work with it", "it's too small for the children", "it doesn't have the selection in equipment", "it's too small for scratch-building", and so on and so forth. Of course, in individual situations these objections all have merit, but it was also the inevitable reaction to something new.
While N scale still only attracts about 20 per cent of modellers (proportionately more in Britain and Europe than in North America), I believe this number will continue to increase as space and affordability pressures, the development of superior motive power mechanisms, the miniaturization of electronic technology, improving choice in RTR (ready-to-run) models, and above all the availability of DCC control with sound and lighting will persuade more and more modellers to give this scale a trial.
The Pros and Cons of N Scale:
The overwhelming advantage of N Scale is that it has the potential for a sophisticated and extensive layout in larger spaces, or alternatively it is a prospective excellent solution for a reasonable operating layout in a restricted space.
But there are some drawbacks:
DCC versus DC:
For a modeller absolutely new to the hobby and venturing into any scale it makes total sense to opt for DCC (Digital Command Control, the electronic method of train control by means of signals transmitted direct to an on-board receiver on each locomotive, making block wiring and cab control obsolete), as the means of control, since it is a computer-age application that will continue to develop. Certainly it is gathering momentum in N scale as manufacturers are now retailing "decoder-ready" (that is to say, a connection and space for the necessary microchip receiver on board the locomotive) and DCC-equipped locomotives. The major benefits of DCC (with the much simplified wiring as a given), are the achievable very realistic scale speeds, the ability to run more than one locomotive independently of each other on the same track, and of course the delight of on-board sound, which will almost certainly not be long in arriving for N scale.
It is good advice to do one's research homework and to select a DCC brand that conforms to NMRA standards and will be expandable as the layout and the locomotive stable continue to grow.
And one more thing - the digital nature of DCC is sure to intrigue the younger generations that we are so anxious to attract into the hobby ...
For those modellers already in N scale and operating with DC (Direct Current or Direct Control) and wanting to move to DCC, it will make a decision necessary whether to rewire their layouts and to retire their older locomotives. As the design of current-generation locomotives has brought much-improved motors with a much lower current-draw, existing modellers may well need to ask themselves how many trains they operate when they are alone at their layout. If the answer is no more than two or three, they may well make a case for themselves to stay with their existing block system (cab control) wiring and circuits, since the primary source of hobby satisfaction is the now available flawless movement of locomotives without hesitation and at realistic crawling speeds, without those jack rabbit starts of yester-year. Yes, on-board sound would be nice, but it is worth several hundred dollars and the hours needed to convert to DCC? (At one's place of work, this would be called "doing a business plan".)
Locomotive performance:
Needless to say, good locomotive performance is of the essence. With the rapid advance of technology, locomotives offered today are infinitely superior in performance to those that were on the market in the 20th century. The old worm-gear drive is almost, but perhaps not quite, a memory! As motive power is at the heart of the hobby, it makes sense to invest in the very best that the market has to offer. Of course, if one is seeking to acquire specific (Canadian) road names, with today's limited production runs and the predominance of U.S. road names, this can become a long-term project. One thing is for sure – if you see a locomotive that you would like to acquire, don't delay – it may be sold out in short order! And one can usually buy an undecorated version and arrange to have it painted and decalled to suit, or learn how to do it oneself.
Once acquired, follow the manufacturer's instruction for maintenance, and keep the "exploded" diagram for handy reference – locomotives usually come ready-to-run from the factory, but when they start to run erratically or with a screeching sound, it's likely time for a few (and only a few – more is not better!) drops of fine oil in the power train, and that means disassembly!
Couplers:
Most N scale locomotives and rollingstock today come equipped with MicroTrains™ (formerly Kadee™) or similar-style (e.g., Accu-mate™) couplers. These make a vast difference to the appearance of an N scale train compared to the traditional "Rapido" (after its original manufacturer) or "Elsie"-style coupler. The Micro-Trains coupler replicates that used on the prototype and works remarkably well. Whether to install magnets for automatic uncoupling (that's what the "tail" or "trip pin" on the coupler is for) is a personal decision. I prefer to use a manual uncoupler (check out that by Rix™) myself as it provides more flexibility in switching operations.
Track – Code 80 versus Code 55 rail:
Traditionally, Code 80 (that is a rail height of 0.080 inches) has been "standard" for N scale ever since its first appearance. However in the past few years, Code 55 has been on the market for better scale appearance, and locomotives and rollingstock new on the market have finer wheel flanges to accommodate that.
However Code 80 continues to be used (as is Code 100 for H0 scale, although Codes 83 and 75 are also offered in that scale), and for a modeller new to the hobby that is another decision to be made. I am of the view that judicious ballasting goes a long way to disguise the over-scale appearance of Code 80 without making N scale track-laying even more challenging than it is now, but that is another personal view of my hobby.
Track laying:
Whether in DC or DCC, careful track-laying is the key to N scale operational enjoyment and good locomotive performance. N scale, much more so than the larger scales, does not take kindly to indifferently laid track. It has to be perfectly level and straight, and where there are curves on gradients, they must be carefully banked (super-elevated) so that 3-axle trucks in particular can negotiate them without derailing. As with all scales, laid track should be carefully tested with a variety of motive power and rolling stock to ensure that the clearances are adequate, and that the wheels perform well through turnouts and crossings. One final tip: do not pin too slavishly or too deeply - it may throw both gauge and level out of alignment and cause derailments - once you have eliminated kinks or "doglegs", let the track find its own horizontal level.
Track formations:
One of the admitted advantages of the larger scales is the ready option of building one's own track, but in N scale that is something for the very-advanced skilled modeller. Most N scalers choose one or more of the ready-made track systems. As it happens, I am a fan of Peco™ and flexible track, but chances are that any one manufacturer will not provide all of the desired track and turnout formations. So by all means research the track formations and turn-outs offered by different track manufacturers. And bear in mind prototypical appearance – for instance double- and single slips are great formations but never did appear in North American branchline operations. Similarly, No. 6 or higher turnouts are definitely preferable to No. 4's anywhere on any layout. Compromises do of course have to be made for space reasons, but if at all possible, if you have to use No. 4's, confine them to the yards or to a non-prominent location.
Minimum radius:
There is no disgrace in 9" radius curves, but creative scenery design can hide or disguise those unprototypical sharp curves. However, do ensure that no radius anywhere is less than 9" (unless it is a mining layout with dinky motive power and 70t ore cars!).
However, space is always a consideration, but for mainline operations, try for a 10 or 11" radius at a minimum. Some equipment and rollingstock with longer wheelbases may have difficulty with 9", and even if they do negotiate that tight a curve, will certainly look rather toy-like.
Rollingstock:
Wherever possible, do weight the rollingstock for better adhesion. For bulkhead, flat, hopper and gondola cars, this comes naturally by devising loads of various kinds – and it helps make the railway look like a prototypical operation – no railway stayed in business by running empty cars all over the place. For boxcars, reefers and cabooses (if you're into pre-1980 railroading!), here's a tip. Go to the local hardware store, show your ID and buy a small tin of .177 cal (4.5 mm) air rifle pellets (usually 200 to a tin). Remove the body of the car and there will usually be a metal plate on the frame, included to provide some basic weighting. Apply Welbond™ or similar adhesive to the plate and place two rows of 4 or 5 or 6 pellets (depending on the length of the car) and let it set. Done. Passenger cars usually come heavier ready-made, but one can install commercially-made interiors or small metal slabs for greater stability. In all cases, remember the natural centre of balance – any weighting should be evenly distributed.
Scenery:
A bonus of being in N scale is the opportunity for those of us who have no special skills for detailed scenery- and structure-making to produce a credible railway environment. (Why – because it's a smaller scale, one has a better chance at "fudging it" Now there's a confession!). On the other hand, there are modellers who become so fascinated by operations that they don't "get around" to scenery, but as I see it, a model railway without scenery is rather like a skeleton: it demonstrates functional operation but has no eye appeal whatsoever (except perhaps to an anatomist).
When designing your scenery, remember the importance of perspective. Background buildings should be closer to Z scale, or even smaller, depending on the implied distance. Especially if the plan is for an extensive layout, it becomes very important to provide the illusion of distance. See my article The Credible Model.
Also, as with any layout, ensure that you can reach any part of it to uncouple or to re-rail, and that you can get into whatever you enclose, whether this is by means of a "pop-up" or "lift-out". To that end, much of the scenery on my layout can be simply lifted off the layout to get at the problem. Also a straightened wire coathanger but with a small 90 degree hook on the end can be used to retrieve anything that has come to grief inside a tunnel, but be careful you don't wreck the couplers, paintwork or any superstructure in the process! Just tease it out VERY gently!
Some common "operating" trouble-shooting tips:
(Note: Not by any means exhaustive as to problems or solutions! Some of these are applicable to DC control. Some solutions are self-evident.)
Layout or track section is electrically "dead" - see also below "Locomotive stalls - no power":
Occasionally a spontaneous uncoupling will defy identification - if all else fails, arrange the offending cars elsewhere on the train, or simply turn the car round. Sometimes that solves the problem - don't ask why, this is model railroading, we're not supposed to have all the answers and you're supposed to be having fun!):
Remember that whatever one's choices, above all model railroading is intended to be fun and relaxation.
While the hobby and the layout can certainly have its frustrating moments, do remember that there is nothing that can't be solved with patience, creativity and perseverance.
I declare my bias. I happen to be an "N scaler" and have been so continuously from the 1970s. I converted from my British-prototype layout when N scale was still very much in its infancy and Minitrix and early Arnold-Rapido locomotives were "state-of-the-art" little marvels of their day. I was attracted at that time to N scale, because I could not create credible scenery in 00, yet had difficulty with the slightly under-scale gauge appearance of 16.5 mm for the British prototype. (Oh yes, I knew about EM gauge, but did not have the confidence or inclination to get into it.)
The Emergence of N Scale:
When N Scale appeared, it endured the same sort of negativity as did H0 scale when it first replaced 0 scale as the predominant residential model railway scale. The arguments were along the same lines: "oh it's cute, but you need a jeweller's kit to work with it", "it's too small for the children", "it doesn't have the selection in equipment", "it's too small for scratch-building", and so on and so forth. Of course, in individual situations these objections all have merit, but it was also the inevitable reaction to something new.
While N scale still only attracts about 20 per cent of modellers (proportionately more in Britain and Europe than in North America), I believe this number will continue to increase as space and affordability pressures, the development of superior motive power mechanisms, the miniaturization of electronic technology, improving choice in RTR (ready-to-run) models, and above all the availability of DCC control with sound and lighting will persuade more and more modellers to give this scale a trial.
The Pros and Cons of N Scale:
The overwhelming advantage of N Scale is that it has the potential for a sophisticated and extensive layout in larger spaces, or alternatively it is a prospective excellent solution for a reasonable operating layout in a restricted space.
But there are some drawbacks:
- Not all modellers are comfortable in working in this scale – it does require fine motor skills and to be sharp-of-eye and steady-of-hand.
- Ready-to-run offerings of equipment (locomotives), rollingstock and structures are not nearly as plentiful and diverse as for H0 scale, although manufacturer support has been steadily improving.
- It is not suitable where younger children are to be involved in the project for the required motor skills in handling the delicate equipment.
- Digital Command Control is now state-of-the-art in the hobby, and the required miniaturization for N Scale has only arrived in the past few years, with on-board sound that fellow-hobbyists in the larger scales have been enjoying for some years now, still very much a novelty.
DCC versus DC:
For a modeller absolutely new to the hobby and venturing into any scale it makes total sense to opt for DCC (Digital Command Control, the electronic method of train control by means of signals transmitted direct to an on-board receiver on each locomotive, making block wiring and cab control obsolete), as the means of control, since it is a computer-age application that will continue to develop. Certainly it is gathering momentum in N scale as manufacturers are now retailing "decoder-ready" (that is to say, a connection and space for the necessary microchip receiver on board the locomotive) and DCC-equipped locomotives. The major benefits of DCC (with the much simplified wiring as a given), are the achievable very realistic scale speeds, the ability to run more than one locomotive independently of each other on the same track, and of course the delight of on-board sound, which will almost certainly not be long in arriving for N scale.
It is good advice to do one's research homework and to select a DCC brand that conforms to NMRA standards and will be expandable as the layout and the locomotive stable continue to grow.
And one more thing - the digital nature of DCC is sure to intrigue the younger generations that we are so anxious to attract into the hobby ...
For those modellers already in N scale and operating with DC (Direct Current or Direct Control) and wanting to move to DCC, it will make a decision necessary whether to rewire their layouts and to retire their older locomotives. As the design of current-generation locomotives has brought much-improved motors with a much lower current-draw, existing modellers may well need to ask themselves how many trains they operate when they are alone at their layout. If the answer is no more than two or three, they may well make a case for themselves to stay with their existing block system (cab control) wiring and circuits, since the primary source of hobby satisfaction is the now available flawless movement of locomotives without hesitation and at realistic crawling speeds, without those jack rabbit starts of yester-year. Yes, on-board sound would be nice, but it is worth several hundred dollars and the hours needed to convert to DCC? (At one's place of work, this would be called "doing a business plan".)
Locomotive performance:
Needless to say, good locomotive performance is of the essence. With the rapid advance of technology, locomotives offered today are infinitely superior in performance to those that were on the market in the 20th century. The old worm-gear drive is almost, but perhaps not quite, a memory! As motive power is at the heart of the hobby, it makes sense to invest in the very best that the market has to offer. Of course, if one is seeking to acquire specific (Canadian) road names, with today's limited production runs and the predominance of U.S. road names, this can become a long-term project. One thing is for sure – if you see a locomotive that you would like to acquire, don't delay – it may be sold out in short order! And one can usually buy an undecorated version and arrange to have it painted and decalled to suit, or learn how to do it oneself.
Once acquired, follow the manufacturer's instruction for maintenance, and keep the "exploded" diagram for handy reference – locomotives usually come ready-to-run from the factory, but when they start to run erratically or with a screeching sound, it's likely time for a few (and only a few – more is not better!) drops of fine oil in the power train, and that means disassembly!
Couplers:
Most N scale locomotives and rollingstock today come equipped with MicroTrains™ (formerly Kadee™) or similar-style (e.g., Accu-mate™) couplers. These make a vast difference to the appearance of an N scale train compared to the traditional "Rapido" (after its original manufacturer) or "Elsie"-style coupler. The Micro-Trains coupler replicates that used on the prototype and works remarkably well. Whether to install magnets for automatic uncoupling (that's what the "tail" or "trip pin" on the coupler is for) is a personal decision. I prefer to use a manual uncoupler (check out that by Rix™) myself as it provides more flexibility in switching operations.
Track – Code 80 versus Code 55 rail:
Traditionally, Code 80 (that is a rail height of 0.080 inches) has been "standard" for N scale ever since its first appearance. However in the past few years, Code 55 has been on the market for better scale appearance, and locomotives and rollingstock new on the market have finer wheel flanges to accommodate that.
However Code 80 continues to be used (as is Code 100 for H0 scale, although Codes 83 and 75 are also offered in that scale), and for a modeller new to the hobby that is another decision to be made. I am of the view that judicious ballasting goes a long way to disguise the over-scale appearance of Code 80 without making N scale track-laying even more challenging than it is now, but that is another personal view of my hobby.
Track laying:
Whether in DC or DCC, careful track-laying is the key to N scale operational enjoyment and good locomotive performance. N scale, much more so than the larger scales, does not take kindly to indifferently laid track. It has to be perfectly level and straight, and where there are curves on gradients, they must be carefully banked (super-elevated) so that 3-axle trucks in particular can negotiate them without derailing. As with all scales, laid track should be carefully tested with a variety of motive power and rolling stock to ensure that the clearances are adequate, and that the wheels perform well through turnouts and crossings. One final tip: do not pin too slavishly or too deeply - it may throw both gauge and level out of alignment and cause derailments - once you have eliminated kinks or "doglegs", let the track find its own horizontal level.
Track formations:
One of the admitted advantages of the larger scales is the ready option of building one's own track, but in N scale that is something for the very-advanced skilled modeller. Most N scalers choose one or more of the ready-made track systems. As it happens, I am a fan of Peco™ and flexible track, but chances are that any one manufacturer will not provide all of the desired track and turnout formations. So by all means research the track formations and turn-outs offered by different track manufacturers. And bear in mind prototypical appearance – for instance double- and single slips are great formations but never did appear in North American branchline operations. Similarly, No. 6 or higher turnouts are definitely preferable to No. 4's anywhere on any layout. Compromises do of course have to be made for space reasons, but if at all possible, if you have to use No. 4's, confine them to the yards or to a non-prominent location.
Minimum radius:
There is no disgrace in 9" radius curves, but creative scenery design can hide or disguise those unprototypical sharp curves. However, do ensure that no radius anywhere is less than 9" (unless it is a mining layout with dinky motive power and 70t ore cars!).
However, space is always a consideration, but for mainline operations, try for a 10 or 11" radius at a minimum. Some equipment and rollingstock with longer wheelbases may have difficulty with 9", and even if they do negotiate that tight a curve, will certainly look rather toy-like.
Rollingstock:
Wherever possible, do weight the rollingstock for better adhesion. For bulkhead, flat, hopper and gondola cars, this comes naturally by devising loads of various kinds – and it helps make the railway look like a prototypical operation – no railway stayed in business by running empty cars all over the place. For boxcars, reefers and cabooses (if you're into pre-1980 railroading!), here's a tip. Go to the local hardware store, show your ID and buy a small tin of .177 cal (4.5 mm) air rifle pellets (usually 200 to a tin). Remove the body of the car and there will usually be a metal plate on the frame, included to provide some basic weighting. Apply Welbond™ or similar adhesive to the plate and place two rows of 4 or 5 or 6 pellets (depending on the length of the car) and let it set. Done. Passenger cars usually come heavier ready-made, but one can install commercially-made interiors or small metal slabs for greater stability. In all cases, remember the natural centre of balance – any weighting should be evenly distributed.
Scenery:
A bonus of being in N scale is the opportunity for those of us who have no special skills for detailed scenery- and structure-making to produce a credible railway environment. (Why – because it's a smaller scale, one has a better chance at "fudging it" Now there's a confession!). On the other hand, there are modellers who become so fascinated by operations that they don't "get around" to scenery, but as I see it, a model railway without scenery is rather like a skeleton: it demonstrates functional operation but has no eye appeal whatsoever (except perhaps to an anatomist).
When designing your scenery, remember the importance of perspective. Background buildings should be closer to Z scale, or even smaller, depending on the implied distance. Especially if the plan is for an extensive layout, it becomes very important to provide the illusion of distance. See my article The Credible Model.
Also, as with any layout, ensure that you can reach any part of it to uncouple or to re-rail, and that you can get into whatever you enclose, whether this is by means of a "pop-up" or "lift-out". To that end, much of the scenery on my layout can be simply lifted off the layout to get at the problem. Also a straightened wire coathanger but with a small 90 degree hook on the end can be used to retrieve anything that has come to grief inside a tunnel, but be careful you don't wreck the couplers, paintwork or any superstructure in the process! Just tease it out VERY gently!
Some common "operating" trouble-shooting tips:
(Note: Not by any means exhaustive as to problems or solutions! Some of these are applicable to DC control. Some solutions are self-evident.)
Layout or track section is electrically "dead" - see also below "Locomotive stalls - no power":
- The most usual reason is a block toggle switch in the "off" position! After that, a broken main feed wire. Check the terminals at the power toggle switches and the power pack first! The next most common reason, where turnouts are in use that rely on connecting rail electrical contact, is failure of that electrical contact. Clean out the connecting surfaces with fine emery paper (600) and/or adjust connecting and stock rails.
- Short circuit. Treat as an emergency as something could be heating up and melting somewhere. Shut off all electrical sections (blocks) immediately and re-open one at a time until "short" recurs. If it's not something obvious, such as a tool left on the track, the likely culprit is faulty wiring, or a locomotive that's straddled across a reverse loop joint. Tip: If you are using turnouts with live frogs, pay special attention to the manufacturer's wiring instructions. And if you are wiring your layout for the first time - don't do all the wiring and turn on the power - chances are there will be a "short" somewhere and you will have no idea where it is. Electrify one section or turnout at a time, and then check that a locomotive will move in both directions!
- Dead spot, e.g., insulated turnout frog (dirty wheels, dirty track, dirty locomotive pick-up, in the case of a stall on a track formation, the running speed may have been too slow)
- Short circuit (Emergency – shut off power immediately and trace. Common sources of short circuits are reverse loops and live turnout frogs. The reason why it is an emergency is that a "short" can melt plastic wheel components or gears within 30 seconds.)
- No power in section (switch is off, broken feed, poor connecting rail contact)
- Gradient too steep (back up and take another run at it, reduce train length, add another locomotive, reduce steepness of gradient (just like the CPR many years ago on the "Big Hill"!).
- Something is catching and holding train (check tunnel entrances etc., couplings, pin on the track.)
- Locomotive has failed – shut off power to prevent damage to powertrain – possible causes are grit in gears, seized wheels, or in the case of a steam locomotive, wheels gone out of quarter. Needs servicing/repair.
- Reduced power in electrical section (this usually occurs from lack of electrical contact where a connecting rail meets up with the stock rail at a turnout – open the connecting rail and gently burnish inside of both connecting and stock rails with very fine (600) emery cloth. It may also occur because of an insufficient electrical connection at a track joint – the small size of N scale track joiners has a greater potential for more problems than its counterpart in the larger scales.
- Track is out of gauge.
- Something is catching (usually the fuel tank) on the underside of a diesel locomotive (bridge guide rails, a too-sharp down-gradient change).
- Needs servicing/repair. Likely but not exclusive reasons are that the power train has dried out, or there may be grit (loose ballast) in the gears.
- A short circuit that has not yet "tripped" the power source. Shut off power immediately and trace.
- Loss of voltage through current "drop" (needs more feeds, higher wire gauge {especially with a remote control]
- Too heavy a load, or the locomotive has been running for too long (give it the "sniff test", if it smells hot, it's been working too hard or for too long.
- Power source not adequate.
- Somewhere an electrical section (block) is open and another locomotive is also trying to move.
Occasionally a spontaneous uncoupling will defy identification - if all else fails, arrange the offending cars elsewhere on the train, or simply turn the car round. Sometimes that solves the problem - don't ask why, this is model railroading, we're not supposed to have all the answers and you're supposed to be having fun!):
- Couplers are out of horizontal alignment, or a weak coupler (replace coupler or reduce vertical coupler play in the housing with a shim).
- Moving train hesitates while over magnetic uncoupler. The hesitation could be at random for a variety of reasons and is not necessarily correctable for all possible train lengths. My personal preference is to avoid them for that reason and to uncouple manually with an uncoupling tool.
- Bump or unevenness in track, more likely at a track formation (turnout, crossing, etc.).
- Abrupt gradient change.
- The "trip pin" of the coupler has struck an object (usually a diverging rail at a crossing or turnout. If the train speed is high enough, this may also cause derailment). Gently bend the "tail" a millimetre or so higher, using two pairs of needle pliers, one to hold the coupler "tail" at the curve and the other to bend the end slightly upwards.
- Body-mount coupler on too tight a curve (may also cause car to derail). Should not occur with radii greater than 9". If the offending coupler is at a locomotive, marshalling a heavier car behind the loco may solve the problem. Only other solutions are either to ease the radius or restrict that locomotive or car from that route.
- Track is out of gauge ("out-of-gauge" track may occur at curves or if it is pinned down too harshly.)
- Track is uneven (again, track should be allowed to find its own level when being pinned at the time of being laid. Too much pinning, especially near track formations, such as turnouts and crossings, may cause unevenness that will make itself known in operation.)
- Track not joined properly at the track joints. (May also cause electrical problems.)
- The track curve is too tight for the equipment. The absolute minimum radius is 9", and especially with the newer locomotives and the wheel flanges now designed to work with Code 55 track, even a random "tight spot" will cause the locomotive to derail.
- Kink (dogleg) in track, especially at the joints - always ensure that you have a continuing smooth alignment.
- Track is overballasted and the wheel flange is riding up and over the rail.
- Dirt on the wheel surface (dirt accumulates on the wheel running surface as a fine paste until it is close to the edge of the wheel flange and the wheel then rides up and over the rail. Solution: a wheel cleaner for locomotives is a useful investment. On rollingstock, take a small Dremel™ screwdriver and scrape the dirt off – it's a tedious job, but that and coupler adjustment are the model railway equivalents of rollingstock maintenance!) This is an intensfied problem with wheels designed for Code 55 track as the flanges are much finer. This is the major reason for being very careful when applying oil to equipment and rollingstock to be absolutely sure that no oil gets on the wheels themselves as this, once spread onto the rails, will cause that dirt paste to form very quickly. When oiling, one tiny drop will suffice - if a piece of equipment is not running well after being oiled, more oil will not help, it will actually make matters worse.
- Connecting rails at turnout stock rails are not flush. (Note: it is not normally necessary or advisable to file or otherwise adjust the intersecting rails at turnout frogs and crossings as they have been pre-set by the manufacturer, but a fully-closed connecting rail blade may require additional filing so that the transition from the stock rail to the connecting rail is completely smooth. Proceed with gentleness to file the end of the connecting rail when closed to the stock rail with a fine Dremel™ needle file.
- Wheelset is out of gauge.
Remember that whatever one's choices, above all model railroading is intended to be fun and relaxation.
While the hobby and the layout can certainly have its frustrating moments, do remember that there is nothing that can't be solved with patience, creativity and perseverance.