revised 4-Mar-03

This page contains a miscellany of information useful in Templot, and model railway track in general.

For more information about prototype track, see also the real track page in the Templot Companion.

The Gimp

The GIMP is a free image editing package which includes perspective correction tools. This makes it possible to take measurements and make track drawings directly from photographs of prototype trackwork. Click Gimping track photographs for a detailed look at the process and its use in Templot.

You can also use The Gimp in general modelmaking as a way of creating a drawing from a photograph. Click A Gimp example for a worked example.

Industrial Turnouts

Here is some data for use in creating industrial turnouts in Templot. Use this data to set a custom straight switch. The dimensions given are a silly mix of metres and millimetres - direct conversions from what are in fact imperial designs. For example the first dimension in the table is 1.829 metres which is exactly 6ft (72"), 2.743 metres is 9ft (108"), and so on. For BS-95R rail (model code 75) the heel offset is 121 mm (4.75"), giving a heel clearance of 2" for rail 2.75" wide.

Industrial turnout drawing

Industrial turnout data

Crossing data ( BS-95R BH,  FB-109,  BS-110A,  BS-113A-inclined )

Here is some prototype data for crossings. The dimensions given are a silly mix of metres and millimetres - direct conversions from what are in fact imperial designs. For BH the blunt nose width is 19 mm (3/4"). For FB the blunt nose width is 16 mm (5/8"). (Dimensions for GWR and BR(W) BH crossings differ.)

About split-deflection switches

 The following notes apply to UK terminology. In American terminology a "split" switch refers to a standard switch, so called to differentiate it from the much older type of "stub" switch. 

Here is a sketch showing the difference between a standard switch and a "split" switch. The stock rails are shown in black, with the switch blades in blue. For simplicity an undercut (unjoggled) switch is shown. I have greatly exaggerated the angles and rail widths to make things clearer:


In a standard switch (upper sketch) one stock rail is bent or "set" to match the planing angle on the blades, and the other stock rail is left as plain rail. Switches in running lines are always of this type, regardless of any curving of the rails, so that there is no deflection either way to vehicles running at full speed on the main road. Vehicles taking the turnout road, however, are abruptly deflected at the planing angle (in this case to the left when running left to right), and a speed restriction is therefore necessary over the turnout road.

In yards and sidings where speeds are low, if there is a contraflexure (Y-turnout or "negative curving radius" in Templot terminology) with the main road curving away from the turnout road (to the right in this case when viewed from the left of the diagram), it is often the practice to "split" the switch as shown in the lower sketch. This means putting a "set" in both stock rails so that the deflection is shared between the two roads.

If the deflection is shared equally between the two roads (50%-50% split), the switch is symmetrical or "unhanded", and the turnout is usually also symmetrical (perfect-Y) with an equal radius in each road. Where the turnout radii are unequal, it is usual to adjust the proportions of the split accordingly, and the sketch shows a 75%L-25%R split.

Note that the dimension labelled sg (sometimes called the "stock-gauge") is the same in both diagrams, and is the distance between the stock rails at the limit of the blade planing. This dimension is equal to the track gauge plus the railtop width. When making the bends in the stock rails it is essential that this dimension is maintained - it is more important than getting the percentage deflections exactly right.

This process is called "setting the switch". Only the stock rails are affected. The blades, chairs, fittings, timber spacings and all other components are exactly as for a standard switch, and the planing angle on each blade does not change.

Sometimes a joggle is made in the stock rails to protect the blade tips, but the sg dimension remains unchanged. Templot can generate switch templates with or without joggled stock rails in versions 0.71 and later. Joggles are not used on trailing switches in running lines.

The dimension labelled pl is the planing length on the switch blades. It is equal to the total deflection angle for the switch (as a unit angle) multiplied by the railtop width. It is also the same in both diagrams. When constructing model switches, it is important to check the dimension sg between the stock rails at distance pl from the blade tips before fitting the blades. sg can be checked by combining an oddment of rail with a track gauge, or  be measured with calipers (gauge+rail-width).

Here is a handy chart of blade planing lengths and deflection angles for different switches:

switch size total deflection angle
(blade planing angle)
pl planing length
(for 2.75" railtop-width)
4mm scale
7mm scale
A or 9ft 1:24 66" 22 mm 38.5 mm
B or 12ft 1:32 88" 29.3 mm 51.3 mm
C or 15ft 1:40 110" 36.7 mm 64.2 mm
D or 18ft 1:48 132" 44 mm 77 mm
E or 24ft 1:64 176" 58.7 mm 102.7 mm
F or 30ft 1:80 220" 73.3 mm 128.3 mm

These diagrams and dimensions apply to straight and REA semi-curved switches (straight planing). For switches with curved planing the pl dimensions differ but the principles are the same, and the sg dimension is the same.

At the time of writing (October 2000), Templot is unable to generate split-switch templates as a single template. A split switch template can be created by superimposing partial templates, one of which is rotated slightly at the toe (blade tips). There is a step-by-step tutorial sequence showing how to do this.

Later Templot upgrades will include split switches, with the percentage split being infinitely variable from 100% Left to 100% Right by mouse action.

Here is some chairing info for bullhead crossings and REA switches :

crossing chairs

These are the special chairs used at the crossing. The X,Y,Z chairs count back towards the switch; the B,C,D, etc. chairs count out beyond the crossing. The A chair is always under the nose of the vee. Where no special chair is shown in this table standard chairs are used, or sometimes bridge chairs where space is tight. The indistinct dimensions in the notes are 4in, 2ft 6in, 2ft 0in (the latter is for the rail joint). All chairs are central on their timbers, so these dimensions are also the timber spacings.

rea switch chairs

These are the special chairs used for REA semi-curved switches. The numbers are the total for the whole switch, i.e an A switch has 5 P chairs per switch blade.

P chairs are the ones on which the switch blade slides and to which the stock rail is fixed by means of a bolt through the rail web instead of a key. Block chairs come next and hold the both the switch blade and stock rail at the correct spacing (these are handed and numbered 1,2,3 etc.). The bolts and distance blocks fit between the rails to keep everything secure.

So for a B switch each side has (counting from the rail joint) :

2 standard chairs in front of the switch toe,
6 slide chairs,
4 block chairs,
Standard chairs and bridge chairs are then used as space on the timbers permits.

PJ chairs are a later design in which the outer jaw is in the form of a separate spacer block, similar to flat-bottom slide baseplates.

first visit  Q  &  A            latest news            main page top

original screenshots            new screenshots            more  Q  &  A

Templot Companion            Templot reference            this page top

tutorials            Templot email group            downloads


Links to other web sites with information about model railway track. Your site not listed? Please email me.

 I am not responsible for the content of these sites and I make no representation whatsoever concerning their content or ownership. These links are provided here simply as a convenience to you. Listing them here does not constitute any endorsement, sponsorship, or affiliation from me.


1. Scale societies :

Societies supporting specific model railway gauges and scales.

2mm Scale Association

3 Millimetre Society

British 1:87 Scale Society

Proto:87 Special Interest Group (SIG)

Double 0 Gauge Association

American 00 Gauge Special Interest Group (SIG)

EM Gauge Society

Scalefour Society

009 Society

S Scale Model Railway Society

5.5 mm Association


Gauge 0 Guild

The 7mm Narrow Gauge Association

ScaleSeven Group

Gauge 1 Model Railway Association

Gauge 3 Society

2. Other sources of model information:

Historical Model Railway Society

Broad Gauge Society

00-SF notes

Finescale 00 notes

British Nn3

Manchester Model Railway Society (Flat-bottom track notes)

3. Model trackwork parts suppliers and manufacturers:

Russ Elliott's comprehensive list of 4mm scale suppliers

C & L Finescale


The P4 Track Company (NewTrack)

Proto87 Stores

Slater's (Plastikard) Ltd


SMP - Marcway



Colin Craig

Gauge 3 Society - track parts

Peco printable track templates

4. Commercial track builders and layout design:

Stephen Freeman - Model Maker

Just Tracks

Raymond Walley - Layout Design

5. Other drawing software (for use with DXF files exported from Templot):

Google Sketchup  (see your track plan in 3D - create layout buildings and structures in 3D - FREE)

3rd PlanIt  (see your track plan in 3D - simulate train running on it)

6. Templot users own sites:

Grindham (Richard Hall)

Grovenor Sidings (Keith Norgrove)

Adavoyle Junction (Tony Miles)

0 Gauge Railway Modelling (Raymond Walley)

Your site not listed? Please email me.

7. Web discussion forums and email groups with track-related content:

Templot Club




00-SF group

Finescale group

Hand laid track group

Proto87 group

Accu-Trak group

Trackwork group

Model Rail Forum

New Railway Modellers

Your Model Railway

8. Miscellaneous track-related sites:

Permanent Way Institution

BR Structure Gauge dimensions

"Yellow Things" Photo Gallery of P.W. maintenance equipment

Picture gallery of Metre Gauge pointwork

Your site not listed? Please email me.

first visit  Q  &  A            latest news            main page top

original screenshots            new screenshots            more  Q  &  A

Templot Companion            Templot reference            this page top

tutorials            Templot Club            downloads