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The Protofour Manual
Track Laying, Weathering and Detailing
4.1.7

 

Baseboard

 
The baseboard is the foundation of the layout and its characteristics determine to a considerable extent the performance of the finished layout. It is therefore essential to use a suitable material or materials which will offer:

 

 
Modellers have been known to use hardboard, blockboard, marine and other plywood, and various forms of insulation board with varying degrees of success.

 
The MRSG most strongly recommends the use of chipboard or Karlitpanel (®) supported by a framework of timber. Chipboard is produced perfectly flat, it has no grain (therefore it has no tendency to warp), it is sufficiently strong to hold screws and other fixings, and is easily worked with simple hand tools. It has considerable strength and when adequately supported will not distort. However, as with all woods, the edges of the board should be sealed to prevent the absorption of water vapour in humid conditions. There are several standard thicknesses of clipboard; the ½" size is recommended to provide adequate rigidity and standardisation between Protofour layouts.

 
Karlitpanel is designed as a substitute for chipboard and as it is less dense it has advantages especially for portable layouts. It is available in 9mm (3/8") and 12mm (½") sizes but the former size is not really robust enough for baseboard use. It should be used with the woodfibre side uppermost.

 
Timber framing 2 x 4cm or ¾" x 12" minimum section should be used to stabilise the baseboard; the form will depend upon the size and type of layout, but one or more timbers should run lengthwise below the track to preserve levels. Using the chipboard or Karlitpanel method, stabilising base timbers may be added after the tracklaying and before the addition of scenic items. Slots or channels should be provided to allow wiring runs to pass from one part of the baseboard to another.

 
The space between the base of the chipboard and the base of the framing is used to contain wiring and control runs and switch operating equipment.

 
There is a tendency for layouts to be too 'flat' in appearance and this is due in part to the use of a flat surface covering the entire baseboard area. The positions and contours of road, embankment, cuttings and other scenic features should be considered and allowance for variation in levels made during baseboard design and construction. Where track formations occupy a substantial area of the baseboard variations in level can be achieved by removing sections of the foundation board and, in the case of roads, by cutting the board with a panel saw along the 'edges' of the road and forming the road base to the required gradient.

 
Where track density is low the L-girder method of construction has much to commend. A bibliography of articles covering L-girder and other methods of baseboard construction is given in the Protofour Manual Section 4.1.1. "Introduction to Layout Building".

 

Underlay

 
Although it is possible in theory to lay track directly onto the baseboard, the differential expansion of metal and wood leads to considerable strain in the fixings. To prevent this affecting the bonding of the track, and to give a certain resilience and sound insulation to the trackbed, some material should be used as an underlay. This material should be easily cut to provide access to electrical connections, yet sufficiently firm to prevent track bowing with the differential expansion caused by sudden temperature changes.

 
The MRSG recommends 1/8" cork sheet as the ideal solution, as it is not so flexible as rubber or foam plastics, yet sufficiently strong to contain the track.

 
The thickness of the underlay gives a convincing height of 'ballast', in conjunction with the thin sleepers, and is sufficient to contain the connections of dropper wires to Wiring Connector Strips. The material forms an ideal key for PVA adhesives, a neutral colour for trackbed and is unaffected by most paints and solvents, and even where exposed it has a scale texture for the lineside.

 

Adhesive

 
To bond the underlay to the baseboard, and the track to the underlay, it is necessary to use a suitable adhesive. There are many different types of adhesive available to the present day modeller, the problem being to select the type with the appropriate characteristics.

 
The adhesive should be simple to handle, pleasant to work, easy to store and amenable to dilution. It should provide a permanent bond, yet remain slightly resilient to absorb stresses and minimise noise transmission. It should not show through the ballast or discolour the materials. It should be possible to remove the adhesive when desired - without wrecking the track. The adhesive which exhibits all these characteristics is PVA 'White Glue' which can be bought reasonably cheaply. It is highly visible while being applied, but cures to a matt, neutral semi-transparent layer. It may be thinned slightly with water, and hardened adhesive may be softened and removed by the application of methylated spirit.

 
The PVA adhesive is ideal for bonding the Protofour timbers to cork, and the bond is capable of withstanding all model railway operating strains. The slow drying cycle enables adjustments to be carried out after tracklaying.

 

Laying Protofour Track

 
The track diagram should first be determined from Protofour Track Planning Templates, or by the construction templates themselves; this ensures that constructed track is dimensionally the equivalent of the plan. The baseboard should be arranged so as to provide the support for the proposed track layout. The underlay should carry over the area which will be ballasted.

 
Note that in pre-grouping trackwork the ballast tended to be flat across the trackbed area; very early pebble ballast, especially in the Southern counties, was laid over the sleepers and only the ends of the latter were visible. Modern track, carrying higher loads at higher speeds, has ballast heaped up to two feet above the level of the trackbed.

 
Cut the underlay to suit the area of the trackbed and attach it to the baseboard. Clean the baseboard thoroughly, as debris between the baseboard and underlay can lead to an uneven top surface and therefore uneven track levels.

 
Mark the edge line of the underlay on the baseboard, and coat the area with a thin layer of PVA adhesive. Wipe a wet cloth over the undersurface of the underlay and cover this with a very thin coat of PVA to ensure thorough bonding. Lay the underlay in position, and roller it (with a rolling pin...) to to ensure firm contact at all points. Place a piece of chipboard over the underlay and weight it, leaving the unit to set for several hours, preferably overnight. The underlay is now ready for the actual tracklaying.

 

 
Naturally, the system may be altered to suit the experience of the modeller; several sections may be laid at one time, or two independent tracks laid alternately, one being laid as the other is. setting. In any event it is essential to experiment on a small 'unwanted' section of track to ensure that the correct amount of PVA is used. Too much PVA may cause ballast to adhere to the sides of the rail where it can be difficult to remove.

 
Although both pre- and post-grouping practice was to ballast up to the sleeper tops, there are occasional locations, especially in sidings and depots, where the full depth of the sleeper is visible.

 
To reproduce this feature two Protofour sleepers are riveted as one; the underlay is reduced in depth to accommodate the extra depth of the sleepers. The 1/8" cork is replaced by 1/16" cork where double sleepers are to be laid, and the transition is disguised by filling the ballast area with material, gradually reducing the apparent level of the ballast.

 
Ballast is of three main types. Main line ballast is of granite or limestone chips and is correctly represented by Protofour standard ballast. A fine half-inch chip ballast is used in termini and other places where running lines are not expected to sustain high speed. In sidings and depots, cinder ballast is usual, and the individual cinders are of almost powder form after weather has broken them down.

 
The object of ballast, apart from stabilising the track, is to ensure drainage of surface water. Where track is intensively used, or where oil tends to saturate the trackbed, dirt accumulates and the ballast turns to slush. The effect of this deterioration is very characteristic of running shed trackage and is best represented by filling the track area with a thin filler wash. The wash is made by adding PVA adhesive to water, then black or dark grey colouring (gouache or emulsion paint colouring concentrate) and finally Polyfilla or other plaster medium to produce a very wet paste of thin cream consistency. This is brushed over the track to be treated and allowed to settle into all crevices. The rail tops are cleaned but the rest of the trackbed allowed to take on the characteristic dirt-caked appearance.

 

Electrical Connections

 
Wiring Connector Strip is led from below selected sleepers to slots in the underlay. Here, once track is laid, small holes may be drilled through to the underside of the baseboard to allow dropper wires to be bonded below the board, out of sight but instantly accessible for checking. Dropper wires should be placed in these holes and the hooked ends passed through the end hole of the WCS. The electrical connection is made permanent by soldering.

 
Once the dropper wires have been soldered the slots may be filled and ballasted to become invisible. The connections for the switch blades should be left until later.

 

Weathering Track

 
Protofour track, with its natural wood sleepers and timbers and real granite ballast, is correctly textured and of correct colour when laid. However, it does not take long for prototype track to collect the dust, rust flakes, oil, coal and other debris and to become of weathered appearance. This weathering should be simulated to produce the prototypical appearance most appropriate to the model.

 
The effect can be achieved by coating the entire track with a thin wash of 'dirt' in the form of thin paint which dries to form a very thin film of the correct toning.

 
The modern Designers Gouache paints are ideal for this purpose. They are similar to PVA in characteristics and may be diluted to the desired intensity using water; they may be added to PVA adhesive to colour it, or to PVA/Filler mixtures; they are very intense and are most economical to use. As with PVA adhesive, they are inoffensive and pleasant to work with.

 
DO NOT WEATHER TRACK UNTIL IT IS ALL LAID

 
The temptation to 'see what it will be like when it is finished' is very hard to resist, but if one area of track is treated at a different time to another, there will almost certainly be a difference in texture between the two which will detract from the appearance of the layout.

 
To simulate track laid on new ballast, the track units may be given a colour wash before laying. To simulate a weathered track the units should be laid and the entire trackbed given a wash of colour.

 
The PVA adhesive sets to an almost invisible film, and the washes dry to a very thin and semi- water-resistant matt coating. The combination of the two is ideal for the purpose of weathering the track.

 
Use ¼" of Gouache, Black, as it comes from the tube, and 1/16" Rust Red, and add water to give a very thin wash consistency. When the track is thoroughly dry, coat the whole area of the trackbed with wash using a household paintbrush (as used for the PVA) and leave to dry. The timbers will soak up the colour and this will emphasise the grain; the ballast will take on a darker appearance and tone in with the rest of the trackbed.

 
Brushes should be washed under a tap as soon as they have been used; this will remove all PVA/ wash and leave them free and supple. If the PVA has been allowed to harden, wash in Methylated Spirit.

 
USE VERY THIN WASHES ONLY. A THIN WASH CAN BE DARKENED BY A SECOND APPLICATION. A THICK WASH CANNOT BE LIGHTENED.

 

Track Detailing

 
This consists of adding general small items which add to the track's authenticity. The chief of these is chairs and is followed closely by fishplates. The chairs are produced in the form of plastic mouldings. Each chair consists of an outer half (complete with key) and an inner half; the halves are moulded on sprues which act as carriers while fixing them in place.

 
Apply adhesive to the concave inside of the moulding, place the chair over the rivet, and cut it from the sprue using a single-edged razor blade.

 
Fishplates are produced as a pair connected by a bridge. The bridge is intended to fit into a slot cut into the end of the rail so that the fishplates help to align the rail ends.

 
When these details are added, make up a thin rust/black oil paint (Humbrol Earth and Black are suitable) using sufficient turpentine thinner to make the paint flow into the crevices without allowing the rail metal to show through. Coat the sides of the rail and the chairs with the paint. Clean off the heads of the rails first using a tissue and later the glass fibre brush.

 

Turnout Operating Units

 
In fitting units for the operation of turnouts we are trying to achieve:

 

 
Protofour Turnout Operating Units are produced in three forms, Type A for normal operations, Type B for use in double slips and Type C for catch points.

 
The Type A unit consists of a plastic bar sliding in an aluminium channel. Attached to the bar are two stainless steel tubes into which fit two cranked nickelCsilver wires. An 8BA bolt, fitted with two adjusting nuts and a solder tag, is fitted to the end of the bar for connecting the power source. The unit is secured to the underside of the baseboard by two 5/8" roundhead screws.

 
The Type B unit is similar except that the bar is longer and contains an extra pair of tubes and wires.

 
The Type C unit is identical to Type A except that only one tube and control wire is provided.

 
The units are designed to fit below a baseboard utilising 1/2" chipboard and 1/8" cork underlay, in which circumstances the steel tubes will automatically position themselves flush with the top surface of the underlay. Use of thinner baseboard materials will necessitate packing the unit, while thicker baseboards may be accommodated by extending the wires in the tubes.

 
The units may be fitted to the track at any time after laying. First mark the underlay where the ends of the switch blades will lie, then drill two 10mm (3/8") holes at 24mm centres, one for each blade, to allow the tubes to be positioned and to move freely. Where track has already been laid and ballasted, clean awaythe ballast near the switch blade ends, and drill two 3mm (1/8") holes immediately outboard of the stock rails. Using these as a guide, enlarge the holes from below to not less than 1/4" diameter, taking care to leave the track undisturbed.

 
P4 track template with sleepers stuck to tape. When the holes are prepared, offer up the unit from below, and check the freedom of movement of tubes and wires; mark the positions of the securing screws, and fit the unit into place.

 
The unit is now ready for soldering the nickel-silver wires to the switch blades. For this purpose a set of Switch Blade Gauges is used. These determine the correct gap between the switch blade and the stock rail when the switch is reversed.

 

Clipping switch blades to rail prior to soldering Clipping switch blades to rail prior to soldering

 
Clip one switchblade to the stock rail using the Silver clip from the gauge set and solder the wire to the switch blade using solder paint or solder cream. Now, with the Silver clip, clamp the second switch blade to the other stock rail at (A) and insert the Blue gauge in position (B) so that the gap between the stock rail and the heel of the switch blade is correctly set by the centre prong of the gauge, leaving the outer prongs to hold switch blade and stock rail securely. Place the Green gauge in position (C) in the same manner at the toe of the switch blade so that only the tip of the blade is held in the gauge. Solder the second wire to the second switch blade, rotating the wire in the tube as necessary to give a close fit.

 
Remove gauges and clips and operate the switches, checking that the blades fit snugly against the stock rails. If necessary, the blades should be carefully scraped to improve the mating between stock rail and switch rail. Replace the clips and gauges and, using a fine wire, place a small dab of epoxy resin, e.g. Araldite etc., on the joints of the wires and tubes while the blades are clamped in position.

 
The baseboard holes are covered by a paper strip, subsequently carefully ballasted, which contains slots which allow unrestricted movement of the wires. The operating unit is now almost invisible.

 
The above programme is followed for double slips, using Type B units, with the provision of two sets of holes instead of one. Both sets of switch blades at each end of the slip are operated in unison by a single lever, so that two levers control all roads through the slip. This facilitates the simplest wiring of double slips.

 
Connection from the lever or motor to the unit is by means of a wire, if necessary containing an omega loop to absorb excess movement. This is attached directly to the solder tag, and fine adjustment is carried out using the twin nuts on the thread of the bolt.

 

Tie Rods

 
Tie rods must be added to complete the prototypical appearance of turnouts. The function of the tie rod in full size practice is to ensure the correct spacing of the switch blade pair. Pre-grouping rods were generally circular in section, while more modern bars are rectangular.

 
Protofour circular section rods are made from nickel-silver wire, one end of which has an insulating coating which is visible as a gloss when viewed in a suitable light. Two types are provided. Type A is used for simple turnouts. Where double slips, tandem turnouts etc. occur, the tie rods pass below other rails which they must not touch in order to preserve electrical insulation. For this purpose Type B, which has a deeper form is used.

 
To fit the tie rods, holes are drilled where indicated in the switch blades according to the turnout templates. For the uninsulated end a No. 76 drill is used; for the insulated end use a somewhat larger drill - No. 70, in order that the insulation is not damaged. Only the minimum length of drill should project from the pin chuck when drilling holes, otherwise there is a high risk of drill breakage through mishandling.

 
Solder the uninsulated end into one blade after centreing the rod between the blades. The insulated end is secured in the slightly larger hole with a smear of epoxy resin such as Araldite etc. Great care should be taken to ensure that the insulation is not stripped while manipulating the rod into position.

 
Where possible an electrical check should be carried out after installation, either by the use of a suitable continuity meter or, alternatively, by connecting a 12v lamp bulb (car headlamp etc) in series with the 12v output of the power unit and connecting the leads to the switch blades. With the power unit full on there should be no glow in the lamp. This is assuming that the remainder of the electrical connections in the turnout are satisfactory.