Märklin’s track makes things easy for you. With a moderate amount of care and effort, you can build a layout that will operate reliably.  Track geometry has always fascinated me. Model track design is not complicated at all, since all the design of the track pieces has been done for you by Märklin.

Märklin has created different pieces of track that can be put together in a variety of ways to give different results. If you take a look at one of their track plan books, you will see that they have provided you with a shopping list and diagrams showing you where to place the different pieces of track. Also, a track plan book shows you where to hook up wires for the various operating devices.  If you plan to cookbook your layout by following the plans exactly, you can easily get your track set up, and press on to the other phases of completing the layout.  If you plan to modify the existing plan, or if you want to design your own layout, knowledge of the track pieces will prove to be helpful.

The basic track set (below) has elements which are curved and two straight pieces.  However, the curved track pieces are not .  There are two different kinds of straight pieces and two different types of curved pieces.

Courtesy Märklin

One straight track section in the loop is the 8500 piece, the basic track element in the Märklin track product line.  The other section of straight track, the 8590, has two contacts off to one side of the track.  It is the same length as the 8500, but allows you to connect the track layout to the power supply in order to control the train's operation.

Courtesy Märklin

The transformer, which controls the train’s speed and also provides power for accessories, is connect to the track layout with the 8590 terminal track.  One rail is connect with red wire to the red connection of the transformer and the other connection is made with a brown wire.  In most cases, which rail gets the red wire is not important, but if you are planning on using overhead catenary wire and operating a second locomotive from that catenary wire, then the knowledge of which rail is the “red” rail will become important.  This issue is discussed here.

When you fit all of the pieces of curved track together, they form a circle with a diameter of 15-45/128 inches (from the center of the track on one side to the center of the track on the opposite side).  If the 45/128 fraction appears to be quite odd, that's because the Märklin track is laid out using metric measurements.  You will find the equivalent figure of 390 mm to be much easier to use than the fractional inches shown above. Please note that when talking about track circles, we usually talk in terms of the radius (the distance from the center of the track element to the center of the circle) of the track, so the circle of track that came with the starter set is 195 mm radius, half of the diameter.

OK, so much for the dimensions of the circle of track.  You may wonder why there are different curved pieces in the starter set.  All the pieces are built to follow the radius of 195 mm.  Yet one type of 195 mm radius curved track is longer than the other. Twelve sections of the shorter pieces of track, the 8521’s, are needed to form a complete circle, while only eight sections of the longer pieces, the 8520’s, are required to make a circle, as shown in figure. As you have discovered, these pieces can be fit together in any order to form the completed circle, but when you add the straight pieces of track, you have to set the curves up more carefully so that things come out even.

The reason for the mixture of curved pieces becomes more apparent when you add the various track extension sets.  Such extension sets are common with European manufactured model trains and the Märklin track extension sets are discussed here.

If you look on the bottom of each piece of track, you will also discover that the Märklin factory has been sporting enough to identify the track by part number, so if you get the pieces mixed up, you can determine which piece is which. In all, there are three different track radii:

Courtesy Märklin

A larger radius curve allows you to have two tracks running side by side (parallel).  The 8530 is built to produce a circle of 220 mm radius; like the 8520, the 8530 requires eight sections of track to complete a circle.  The 8531 is like the 8521 in that it requires 12 sections of track to complete a circle.  Likewise, there is a smaller track radius, the 8510, which is 145 mm radius.

Another way to describe the different curved tracks is to identify them by the portion of the circle which they represent.  That is, the 8510, 8520 and 8530 track sections are 45° pieces, each representing 1/8^th of a circle (45° X 8 = 360°). Likewise, the 8521 and 8531 pieces are 30°, each representing 1/12^th of a circle.  The 145 mm radius does not have a 30° piece. As we go on, you will discover two other curved pieces, the 8529 and 8539 track contact sections, each of which are 30°.

There is one more curved piece, the 8591. Unlike the other track pieces, this section does not form a complete circle. Rather, it is a compensation piece, designed to be used with the track switches and crossings.

Courtesy Märklin

Going back to the basic 8500 straight track, there are a variety of additional straight pieces that allow you to make up different track layouts. 

The 8506 is another complementary track piece, used with a track switch called a double slip or with a crossing.  The 8506 evens out the different track lengths.

The 8507 is used to make a parallel track that lets you place a station platform (8961) between the tracks. This is quite helpful if you plan to do a station scene with more than one station track. 

Other straight track pieces are the 8587, which allows you to uncouple cars. Two other straight pieces are  the 8588, an isolation track piece used primarily with signals and the 8589 track, a circuit track like the 8529 and 8539, all of which are discussed in the Automatic Operation pages.

Finally, there is the 8594 track section, which is the equivalent of six pieces of 8500 or three pieces of 8505.  This is very helpful when you have long lengths of tangent track. The 8594 can be bent into a curve if you cut the bottom of the crossties (a small instruction pamphlet is included with the track), and it can be cut to specific lengths. The 8594 allows you to create flowing curves with a natural appearance.

Turnouts

We often use the word turnout to describe a track switch. Turnout is a civil engineering term that describes a track section in which the train can go either straight, or turn out. We use the word turnout in model railroading to mean this piece of track, not an electrical control switch. The turnout is what really makes railroads fascinating, for it affords the train opportunities to go in different directions, to do different things.

Märklin offers several different types of turnouts; the 8562 is a left-handed, remote-control turnout.  This means that from one end of the turnout, looking toward the straight and diverging routes that the train can take, the diverging route turns out to the left. Since the 8562 is a remote turnout, you can operate the turnout either manually or by using electrical current from a remote location (the control panel). Similarly, the 8563 is a right-handed remote turnout.  More about remote operation in the electrical pages

The 8562 is on the left and the 8563 is on the right.

Note that the straight segment is 110 mm long, corresponding to the 8500 straight track while the curved portion of the turnout is a 13° curve of radius 490, corresponding to the 8591 curved piece.  Both of these turnouts are remotes.

Internally, the remote turnout has two coils of wire; when one coil has electric current passed through it, a small slug of metal is drawn toward the coil, causing the moving points of the turnout to go into position.  The moving points of the turnout will stay there until an electric current is passed through the other coil (or the turnout is thrown by hand), which will move the points over to the other position. 

It is very important to note that the current which flows through these coils should be momentary; that is to say, the current should not run through the coil longer than absolutely necessary to align the points.  Should the current continue to flow for more than a few seconds, heat will build up in the coil, causing it to burn out.  There are replacement parts for these coils, so all is not lost should an accident happen. The turnout can always be operated by hand.

For circumstances where a remote turnout is not needed or wanted, Märklin offers manual turnouts; the 8565 (left turnout) and 8566 (right turnout) are the only manual turnouts available.

It should be noted that in the early days of Z-Scale, Märklin only sold turnouts in pairs.  Eventually, this limiting practice was eliminated in favor of singly sold turnouts.

Curved turnouts are also available. In the normal turnout, one route is straight, the other curved.  The curved turnout has two routes with curves of different radii. By using the 8568 (left turnout) and 8569 (right turnout), you can place a turnout on a curved segment, allowing you to put much more track in a given space. These turnouts can be operated either manually or by remote control.

There are two other pieces of track which you probably have noted, the 8559 and the 8560.  The 8559 is called a crossing, where one track crosses another track.   This piece is sometimes mistakenly called a “crossover”; a crossover refers to another track situation in which a pair of turnouts are set up to allow the train to cross over from one parallel track to the other.

The 8560, called a double slip, is built to the same dimensions as the 8559, but features two sets of moving points.  It is like having two turnouts, so the train can either go straight through the crossing, or it can turn out from one path to the other. Thus, it acts as both a crossing and a turnout.

Finally, the 8993 set of tracks helps you deal with an electrical problem that occurs with two-rail track model trains such as Mini-Club. When the track is looped back upon itself, you encounter a short circuit. Since you apply positive (+) and negative (-) DC voltage to the individual rails, you do not want the rails to connect to each other except through the motor of the locomotive.  The turnouts are electrically insulated and specially wired so that the current is directed to the proper rails of the two routes.  In the return loop, the positive (+) rail ends up getting connected to the negative (-) rail, and vice versa.

There are several ways to handle this, and the 8993 track set is one of them. You will note that the pieces are numbered 1, 2, and 3. By placing these sections in numerical order in the return loop, you can eliminate the short circuit problem. The train must always pass through the loop in one direction, but the internal circuitry of the track sections eliminates complicated wiring.

Courtesy Märklin

   There is more about return loop wiring here.

Distances

Finally, a few numbers. The normal distance between parallel tracks is 25 mm; this is established when you use a straight turnout with either the 8591 curved track or with a second turnout.  If you are planning freestanding platforms between tracks, the magic number is 50 mm; use both the 8507 straight track coming off a turnout and either another turnout or the 8591.  This also is handy if you want to connect 8510 and 8520 parallel curved segments.  If you are planning for one track to go over another, the minimum vertical clearance is 40 mm, the distance between the top of the rails and the bottom of whatever is above that point (such as a bridge).  If you use the graduated pier sets, you do not need to be too concerned about gradients (which are the rates at which the tracks rise), but if you are cutting your own grades, try to keep the rate of rise under 4 percent.  This means that the tracks rise four mm every 100 mm in distance (the approximate size of the 8500, which is 110 mm).  You can use steeper grades, but doing so will reduce the number of cars the locomotives are able to pull up the grade.

If all this seems like drudgery, I admit that I am sympathetic. One of the hallmarks of early train ownership is an eagerness to get rolling, right now.  I still feel that way from time to time.  However, let me counsel you that the time spent planning your ideal layout will repay you many times over. You will be spared countless return trips to the hobby shop for just one more piece of track. You will avoid the purchase of inappropriate buildings or scenery.  You also will be spared disheartening surprises, such as discovering that there is no access to the tunnels you have made, or that your dream layout cannot fit into the coffee table you have built. The time it takes to draw up five or six layouts can't possibly equal the time it takes to construct one real layout, and the week or two it takes to plan the layout will help you bring your ideas to fruition.  It is worth it.

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