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Basic Elements of Track Design
In this module we will examine the fundamental building blocks of track design; the pros and cons of each; pitfalls to watch out for to ensure high operational reliability and software tools you might use to make things easier. Layout design elements are just that, common track formations that you are likely to incorporate in any track layout because they are essentially recognisable, reflect prototype practice, are operationally necessary or simply appealing to the eye.
Single, Double, Triple or Multi?
Before we go on to study basic track design concepts and the like we need to address what type of layout you envisage constructing as this will govern which aspects you need to concentrate on.
All the track configurations we have covered so far feature a single-track system but it goes without saying that you are free to adopt any number of tracks running in parallel as commonly found on many of the world’s railways:
Single Track
A single-track railway is where trains traveling in both
directions share the same continuous track between locations
and is typically found on small branch lines where the volume
of traffic does not justify the cost of laying a second parallel
track. There are several railway lines in the UK where
provision was made for a second running line but never
constructed for one reason or another.
Early railways in the United States were also built as
single-track more for reasons of cost and distance and
many preserved lines arestill run in this way.
Bi-directional single line running brings its own complications. How can two trains pass each other safely and what signalling arrangements will best safeguard operations?
Double Track
As the name implies a double-track railway usually has two parallel running tracks spaced sufficiently apart to allow simultaneous train movements in both directions.
In the earliest days of railways in the United Kingdom, the majority of lines were built as double-track and single-track lines were officially regarded as incomplete. Double track lines are generally associated with mainline traffic between major conurbations.
Triple Track
Not so common but may be used in certain circumstances such as to allow
slower moving goods traffic to be overtaken by faster passenger trains
(especially uphill) or handle peak time traffic (where they are signalled on
both directions.) This compromise is a lower cost option to a full quadruple
track.
Quadruple Track
A quadruple-track railway (also known as a four-track railway) is a railway line comprising four parallel tracks, with two tracks worked in each direction. Quadruple-track railways can handle large amounts of traffic, and are normally used on very busy mainline routes. Trains are sorted in various ways in order to make maximum use of track capacity and the four tracks are usually paired either by direction (slow/fast in each pair) or by purpose (speed or direction in each pair). On modern railways two of the tracks may be spaced at a greater distance from conventional parallel tracks. This separation allows a faster
journeys on high-speed express trains.
The actual distribution determined for each line can depend on a combination of factors:
Sorting by Speed
Tracks are usually paired with faster express services and slower local stopping trains separated from each other and each having a separate pair of tracks assigned to them. Construction of new double tracks dedicated to high-speed rail alongside existing conventional double track used by regional and local passenger trains and freight trains is a form of quadruple track. It increases the capacity of that route considerably, and allows for significant improvements in inter-city high-speed train frequency with reduced travel times.
Sorting by Distance
Long distance inter-city rail and freight trains are separated from short distance commuter rail. This helps to prevent delays on one service affecting the other, and is commonly seen in metropolitan and heavily populated areas.
“Quadrupling” may also be necessary when a new commuter rail service begins to operate on an existing line. Sometimes the local trains have separate technology, such as electrical system or signalling, which requires strict separation
Sorting by Destination
When a quadruple track line divides to different destinations part of the way along the route, trains need to be sorted by their ultimate destination.
Sorting by Passenger / Freight
Passenger trains and freight trains can be separated with each different track.
Other Modes of Operation
Quadruple train tracks do not need to be parallel or even close together. Two double track lines along opposite sides of a river can operate as a quadruple track and examples of this can be found along the Rhone in France and Rhine in Germany.
Operating four separate tracks on a garden layout concurrently can prove very challenging with only one operator. If you fancy creating such a busy railway display with several trains crossing in each direction you might find it easier to install 4 independent loops with a central observation point to simply watch the trains passing by.
Single Track v Double Track?
So we have an idea as to the choice of track formation but which will you choose to adopt and what are the key advantages / disadvantages of the two main options - single or double?
Once again it is your railway and only you can resolve this quandary. As with most topics there is plenty of advice to be found on the subject both on the web and in model railway journals and forums.
If we go through some of the questions raised most often it may help you to maske that initial decision. After all, nothing is final and you can always change your mind, either during the construction phase or at some time in the future. The pre-supposes that you have provided adequate space for such an eventuality. If not any changes can prove problematic and costly.
Operational Feasibility
If you are single operator controlling two trains (or possibly more) simultaneously is quite a tall order. Your eyes are likely to be constantly torn between your two operational controllers and observing the trains on their respective lines to try and ensure that they come to no harm. Don't necessarily rely on Digital Command Control (DCC) making the job any easier either. You will probably need to duplicate your power supplies and invest in additional control equipment and wiring at the very least.
Can you really justify having two tracks if you are operating a prototypical service with extended intervals between passenger and freight trains? There is also the danger that double track layouts tend to develop into "race tracks" whereas single line installations provide much more of an operational challenge and far more interest.
If your railway is intended to replicate a specific place and time you will need to bear in mind the nature of the railway operations during that era to preserve authenticity. In the same way it would not be appropriate to represent a logging line in Oregon or a slate quarry in Wales using mainline track configurations.
If you plan to build a large layout with 'out of sight' sections or intend to be freight intensive and be shunting a lot of wagons in the yard it might be a good idea to think again about dual roads. On the other hand if both trains are just circling two loops in opposite directions it may still work but could become a bit repetitive and even boring to watch.
You might consider having mixed single and double track working to ease the load and vary activities at suitable intervals? Such a hybrid arrangement might involve opting for a double track for a busy stretch of the mainline, near the freight yard or at terminals thus allowing for passenger trains to avoid being slowed down by freight switching (marshalling) movements and single line (with passing sidings) in quieter, open areas and into the mountains.
Affordability
Building a satisfying garden railway with plenty of operation interest is not a particular inexpensive hobby. Having to "double-up" on roadbed, track, wiring and ballast etc. is likely to stretch the budget considerably. In theory you alson need to build up a substantial roster in terms of locomotives and rolling stock. In large scale you are talking a large amount of dough.
Much wider radius curves might be needed and these tend to cost appreciably more in proportion to 'standard curves' (which should be large radius to start with in any case). If expenditure is a major consideration why not plan to have double track in the future (in terms of space considerations) but only instal a single line at the outset?
Space
Space tends to be a lot less of a concern when modelling in an outdoor environment but double tracking will need more room and it is always a good idea to allow for future expansion. Wider curves require wider clearances and the line may need to be longer to adequately represent a mainline as opposed to a small narrow gauge operation.
Train Length
One of the advantages of double tracking is that you don't need to worry about having sufficient space for two trains, travelling in the opposite direction, to pass each other. With single track operation you have to incorporate regular passing spaces by means of a siding or loop to facilitate this manoeuvre. Each of these will need to be at least the length of your longest train which could be 10' or more. The 'rule of thumb' here is apparently to have two more passing sidings than you ever expect to have trains running and have them well spaced apart. Many layouts tend to operate with far fewer than are required. On the prototype passing sidings are situated a lot further apart but as they say, a 20 minute delay on a model is a an eternity.
This is where the double track option comes into its own both in terms of 'overtaking' trains and 'crossing' trains especially where suitable facing point arrangements are incorporated along the permanent way.
Additional Track Maintenance
Summary
As I said at the beginning of this section it is entirely up to you what type of track formation best suits your particular needs and ambitions. You can always draw up two sets of plans, one based on a single track approach and the other involving double-track, and envisage how these might work in practice and what the space, time and expenditure implications are likely to be.
Incidentally railroad regulations in the USA, and many other countries around the world, require trains to keep to the right on double track unless otherwise instructed. In the UK it is the reverse with trains keeping to the left on the same side as road traffic. This possibly dates from the early days of English railways when passenger coaches where sometimes constructed from modified road carriages (coaches). Just as well we are an island!
It goes without saying that the more extensive your track layout becomes the more time you will need to devote to track maintenance as opposed to running trains. The best advice is probably still "keep it small" to begin with as otherwise you may discover that you have created a rod for your own back.
Designing the Model Track Plan
The best advice for any modeller contemplating building a more stimulating layout is to acquire at least one book of railway plans. It does not really matter which scale they are for – the plans are merely to give you ideas as to what is possible. This needs to be supplemented by exhaustive research, both in the model railway press and on the internet, to see what works in operational terms and more importantly which configurations don’t work and need to be avoided.
At the end of this Module I will provide a short list of useful research sites, readily available on the world-wide web, to point you in the right direction. Most of these layout designs are free to use so there is really no excuse for not carrying out the necessary research.
Types of Layout
To my mind the basic layout types can be condensed into 4 configurations as follows:
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Continuous Loop (Circle or Closed Circuit or Oval or Crossover or Figure-of-Eight)
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End to End (or Point to Point)
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Return Loop (Point to Loop or Out and Back or Balloon Loop)
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Complex Operations (Station, Goods Yard, Coal Mine, Switchbacks; etc. featuring complex track layouts and operations
although even some of these could arguably be said to be variations on much the same refrain.
The Continuous Loop
Many of you will be familiar with this implementation as a basic oval of sectional track is often included in a Starter Set which you may have received as a Birthday or Christmas present. This can easily be assembled indoors and saves you going out into the cold of winter to test everything.
From an electrical standpoint it is also comparatively safe provided you observe the instructions.
The initial layout is also easy to extend with compatible track brand and can give tremendous pleasure without even venturing into the great outdoors. The fact that so many enthusiasts do create their railroad empire in a garden
setting and choose to operate in what can prove a harsh environment, year after year (and often well into their dotage
health permitting), is a testament to the immense amount of personal fulfilment and sheer enjoyment to be derived from building a ‘proper’ miniature railway in the backyard.
Closed loops, where the trains can run indefinitely, continuously passing their original starting point again and again until the power is turned off (or reversed), are still very popular even though they do not actually reflect normal prototype railway practice. It can be quite relaxing to watch the train repeatedly run round and round the circuit without operator involvement. In fact, it is relatively easy to reproduce this style of automatic operation in a garden setting without exhibiting the ‘toy train’ look. After a few circuits interest can tend to pall, even to small children, so you will probably spend any Christmas or Birthday money left over on acquiring additional track sections to extend the layout.
Indeed, this track formation is frequently the automatic choice if the intention is to run a line around the perimeter of a garden or yard and is also capable of being easily converted into a point-to-point layout at some future date. There is nothing to stop you creating whatever complex shape you desire provided the circuit (or possibly circuits) is continuous.
The reality that a line is a simple loop can be largely concealed by the judicious introduction of station passing loops, halts, sidings, goods yards, engine sheds, tunnels and branch lines, etc. Even the fact that the layout is flat can be cleverly disguised by adding scenery to the enhance the existing garden You have the choice of packing as much track as you like into a small area or create a feeling of open spaces by keeping the track element to a minimum and adding interest by adding road, paths, appropriate buildings, hedges, trees, fields, etc. just as you might on a typical indoor small-scale layout.
These additional features can add considerable interest and operational scope to such a layout especially if you introduce separate levels allowing the track to weave its way over and under itself at various levels.
There is no reason why you should not also incorporate a parallel second track for mainline running – it is purely a matter of personal preference. Remember the large-scale modeller’s maxim – It’s my railway and I will run it how I like” (although the usual words are not quite as polite).
As is often said, the possibilities are endless and limited only by your imagination, depth of pockets and the space available for your individual layout.
Continuous loops are also ideal for locomotives that are powered by real steam or batteries (especially if there is no Remote Control (R/C)), although it is always advisable to use the widest possible curves.
This video summarises the advantages and disadvantages of continuous loops in general.
Basic Track Layouts Based on a Loop
Here are a series of track designs using PIKO sectional track where the basic circle is progressively expanded into more complex arrangements by the addition of extra track sections.
Basic Circle Expanded to Create Small Oval with two extra straight sections
Oval loops are the most basic form of track plan and capable of infinite expansion possibilities by adding stations, passing loops, sidings, spurs (say to a lumber yard or local industry), tunnels and even branch lines to alternative destinations.
This will never quite disguise the fact that the line is continuous however imaginative the observer might be. Consider the potential offered by "Dogbones" and "Folded Continuous Loops" discussed later in this module, as an alternative.
Extended Oval with Passing Loop
The above two extended oval plans are so popular that Piko have released Track Packs which provide you with just the extra track sections that are needed to expand the oval supplied with a Starter Train Set to complete the installation.
The Dog Bone / Inverted Dog-Bone
Yet another variant of the continuous oval you might wish to choose is the Dogbone which is just an extended oval compressed in the centre portion. Dogbones also have the virtue of being much easier to wire than ‘out and back’ loops.
Single Dogbone
Dogbone 2 with Wider Radius Curves and Longer Straight ‘Dual Track’ Run.
Return Loop (Balloon Loop. Turning Loop, Reversing Loop, Point to Loop)
A ‘Balloon Loop” layout (also known as a turning loop or reversing loop in North American) is a track configuration allows a complete train or rail vehicle to reverse direction without having to shunt or undertake any special manoeuvres. This is frequently employed on high volume unit freight trains such as coal, mineral, bulk liquid or similar commodity consists to speed unloading and return. It can also be used for passenger trains and trams, etc. The design is typified by a distinctive single looped track where the trains leave one location and travel around a reversing loop to return to the original starting point along the same track but facing in the opposite direction.
It is very similar to the end-to-end formation outlined above but with the turning achieved automatically at the far end. This arrangement takes up less space than a conventional oval and gets over the need to reverse the engine at the remote location point (but not at the originating point).
Note: Special electrical wiring is normally required for this operation in order to avoid short circuits.
More information about wiring “reversing loops” can be found here.
This arrangement is not encountered very much on prototype railway lines although many examples exist and it is more commonly found on tram and streetcar installations. Loops are also used at coal mines, grain elevators, power plants and similar large industries where there is a requirement to continuously load/unload a large number of identical cars (sometimes referred to as a "unit freight train".)
A unit freight train (also called a block train) is generally one in which all wagons (cars) are identical or similar in design and appearance which convey the same commodity on a regular basis between two distinct locations.
Whilst a Balloon Loop can be just a single line out and back these days the loop is more likely to comprise a complete circle of track to permit continuous high speed operations with the minimum of signalling complications.
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Return Loop (Loop to Loop)
This continuous design combines two separate “balloon” loops at each end of a single track allowing the locomotive to repeatedly reverse its direction of travel each way without hardly stopping.
This layout is popular with Tram enthusiasts for obvious reasons.
On a model railroad, as with the prototype, reverse loops consume a lot of space but are the fastest way to turn an entire train. One of the most common uses of reverse loops in modern layout design is as part of a staging yard. By incorporating a reverse loop, arriving trains can be quickly turned and readied for their next run.
Just to remind you, this track arrangement requires particular protection devices that automatically activate to eliminate the inevitable short-circuits should a positive+ current come into contact with a negative- one by changing the flow of electric current. There are numerous proprietary solutions on the market to achieve this ‘electrical switching’ and you will need to research these options if intending to adopt this type of track design if you are not proficient in electrical matters.
Figure of Eight
One way to utilise the continuous loop whilst concealing its nature is to employ a crossover (essentially an oval twisted into a ‘figure of eight’) with one track crossing the other at some point on the line either at the same or different levels. Several figures of eight can be rolled over each other at multiple levels to disguise the actual route of the railway. You can also cram a lot of layout into a relatively small space.
You can also flex the figure-eight into two uneven loops to reduce the uniform look and make it easier to conceal:
Here is a rather more complex version of a “Figure of Eight” on one level with a Piko 15 Degree Crossing (it is much easier to use a 45-degree crossing but for some reason Piko do not make one but the LGB version would probably do just as well with a bit of “jiggling”) but demonstrates the concept:
Clearly none of the foregoing plans are prototypical and will not allow much in the way of operational movements but they are intended for an inexpensive starter installation providing interest and enjoyment (albeit with very tight radius curves). However, one can gradually acquire more track and extend the layout further as time and funds permit
Having asserted that none of these continuous loop plans reflect prototype practice I did come across just such a layout plan for HO scale which does come very close. I have considerably simplified the design for larger scale outdoor railway and with imaginative landscaping and additional sidings, passing loops, goods yard and engine sheds you could have a lot of fun, especially so if you choose DCC system which permits more than one locomotive on the same track. However, the layout does take up a lot of space so make sure that you have sufficient room (and the finances) to accommodate it.
Both the foregoing layout plans offer unlimited extension possibilities and also help to disguise the continuous nature of the loop.
Just to reiterate, any basic continuous circuit can be substantially enhanced and extended by the addition of stations, motive power depots, sidings, freight yards, mining or lumber operations, station halts, and branch lines off to create more interest and allow complex shunting operations to be performed. Continuous loops do not have to be boring if one is creative especially if the parts of the layout are hidden from view which helps to disguise the fact that the train is not simply aimlessly going around in circles.
To sum up the closed loop offers endless scope for imaginative creativity and the opportunity to imprint your own individual likes and preferences on your own railroad.
End-to-End (Point-to-Point)
The second type of layout is variously known variously as “End-to-End”, “Point-to-Point”, “Out-and-Back”, etc. is simply a length of track with a beginning and an end. This used to be one of the most common arrangements for a garden railway but can be difficult to operate without some degree of automation which automatically reverses the train after a timed interval at the remote destination.
Notwithstanding its negative points this form of layout probably comes closest to reflecting real prototypical railway operations and has its vocal adherents. However, it can never quite convey the long distances travelled by real railway trains – unless you own a large field of course.
Simple Point - to - Point Layout
As the name suggests this arrangement is a line with a specific destination at each end, typically a station, mine, lumber yard, etc. where the goods, passenger, or mixed train runs from one end of the line to the other at slow speed. It must then be turned around or reversed to return to its original destination. This ‘turning’ operation can be done manually (hand crane) or mechanically (shunting or turntable).
Point-to-Point lines are closer to representing real railway practice and can be improved by creating passing sidings at each end allowing the engine to uncouple and run around (“loop”) the train of passenger cars or wagons and recouple for the return trip. You might also think about adding an engine turntable to perform this operation for added interest. There are also examples of a Wye Point being used although this is fairly uncommon these days.
However, if you intend to construct a more modern railway the need for this type of manoeuvre is largely eliminated as most locomotives of recent eras are capable of “two-way” running.
Once again’ the basic end-to-end configuration is capable of limitless expansion and the addition of scenic features to create more interest and operational scope such as in the example below:
For convenience the above plan has been created using basic Piko Straights, Curves and Points using Anyrail Software but would greatly benefit from wider radius curves and points plus longer straight track sections.
The two points of the line can be located quite a way apart from each other or, better still, placed in relatively close proximity at the starting point for ease of operation thus facilitating manual turning and visual oversight. The latter can be imperative if the other end of the track is a long distance away.
For some reason, and despite point-to-point layouts corresponding more closely to the way real railways operate, this type of layout formation has not proved as popular for garden railways as continuous loop implementations. This experience also tends to differ from layout preferences perceived in smaller scale model railways.
However, you might combine a “Point-to-Point” design with the popular Oval to give you the benefits of both arrangements, viz.
A more complex Point-to-Point Layout
Once again this illustrates the benefits to be gained by "mixing" the basic elements of track design to create a more interesting layout. Experiment with your own ideas or simplify someone elses layout design.
Track Arrangements for Prototype Operation
In order to operate your garden railway in accordance with the prototype you will most likely need to be familiar with the appropriate track formations and installations employed on real railways.
In the next Module 9 we will examine more features that can enhance the operability of your railroad using tried and trusted techniques.