Sarum Bridge - Construction, Tracklaying and Scenery
Construction
Baseboard construction is traditional: a 3mm plywood top on a pine frame, reinforced at the corners with steel brackets. There are no legs, as the layout is intended to sit on a table or similar. The trackbed is also 3mm plywood, supported above the baseboard on lengths of pine moulding for strength. I would normally have gone with an open plan baseboard design for something like this, but given the thin and narrow trackbeds and lack of point motors, etc., it seemed more straightforward to use a continuous top. This also eliminates the need for any diagonal bracing of the framework.
The viaduct is just a piece of pine timber, 65mm x 18mm, with a row of 38mm holes cut in it for the arches, and with the bottom half of the holes cut back into pillars. This is quite practical for T gauge, and might also be a viable technique for a small viaduct in N. The viaduct is surfaced with stone plasticard after installation and tracklaying. The result is just a bit too narrow, so is widened slightly at the top with styrene strips to support the parapets.
The 3mm ply trackbed is supported by pillars mostly made from combinations of pieces of wood of various thicknesses: 3mm plywood and 18mm, 30mm and 42mm pine. Gluing a few of these together allows construction of accurate pillars of almost any height. Some of the secondary pillars are just a piece of plywood on its edge. The height of the station and upper balloon loop was chosen to be 42mm, so I can use a couple of battens of the 42mm wide pine to support the full length and ensure that they are firmly supported and horizontal. The rear straight is also supported by a batten of 42mm pine, which is in turn supported by the usual pillars.
I have gone with a minimum vertical clearance of 1 inch where one track passes over another. That is more than strictly required for T, but allows some room for fingers and track cleaners!. Access to the outer hidden tracks is from the outside of the layout (with cutouts in the backscene structure). The balloon loops require removable scenery - quite challenging, especially figuring out how to conceal the joins - I eventually used thin foam rubber painted to look like hedges.
The maximum track elevation on the layout is 80mm above the lowest point. The viaduct is built on a slope (only 1 in 100) climbing up to the high point near the castle so that the bridge isn't the highest point on the layout.
Trackbed construction and tracklaying (and testing!) had to be intermixed, since the lower level tracks are obscured by the trackbed for the intermediate and upper sections.
Baseboard construction is traditional: a 3mm plywood top on a pine frame, reinforced at the corners with steel brackets. There are no legs, as the layout is intended to sit on a table or similar. The trackbed is also 3mm plywood, supported above the baseboard on lengths of pine moulding for strength. I would normally have gone with an open plan baseboard design for something like this, but given the thin and narrow trackbeds and lack of point motors, etc., it seemed more straightforward to use a continuous top. This also eliminates the need for any diagonal bracing of the framework.
The viaduct is just a piece of pine timber, 65mm x 18mm, with a row of 38mm holes cut in it for the arches, and with the bottom half of the holes cut back into pillars. This is quite practical for T gauge, and might also be a viable technique for a small viaduct in N. The viaduct is surfaced with stone plasticard after installation and tracklaying. The result is just a bit too narrow, so is widened slightly at the top with styrene strips to support the parapets.
The 3mm ply trackbed is supported by pillars mostly made from combinations of pieces of wood of various thicknesses: 3mm plywood and 18mm, 30mm and 42mm pine. Gluing a few of these together allows construction of accurate pillars of almost any height. Some of the secondary pillars are just a piece of plywood on its edge. The height of the station and upper balloon loop was chosen to be 42mm, so I can use a couple of battens of the 42mm wide pine to support the full length and ensure that they are firmly supported and horizontal. The rear straight is also supported by a batten of 42mm pine, which is in turn supported by the usual pillars.
I have gone with a minimum vertical clearance of 1 inch where one track passes over another. That is more than strictly required for T, but allows some room for fingers and track cleaners!. Access to the outer hidden tracks is from the outside of the layout (with cutouts in the backscene structure). The balloon loops require removable scenery - quite challenging, especially figuring out how to conceal the joins - I eventually used thin foam rubber painted to look like hedges.
The maximum track elevation on the layout is 80mm above the lowest point. The viaduct is built on a slope (only 1 in 100) climbing up to the high point near the castle so that the bridge isn't the highest point on the layout.
Trackbed construction and tracklaying (and testing!) had to be intermixed, since the lower level tracks are obscured by the trackbed for the intermediate and upper sections.
Tracklaying
The layout uses flexi track throughout, and learning how to work with the T gauge track was a new experience. The flexi track is harder to handle than the N gauge equivalents. As soon as a length is removed from its plastic tube, it tends to twist like a corkscrew. When bending it around sharper curves, the twist becomes even more pronounced. As a result, the track really has to be firmly secured to the baseboard. It is also quite delicate - rough handling can pop the rails out of the chairs - I did this to the first length, but took more care and there was no trouble with the rest of them.
After a few small experiments, I settled on using superglue to attach the track directly to the plywood trackbed. You only have 15-30 seconds before this sets, so it needs to be bent and fit-checked first. I hold the track down with some combination of fingers (moving them frequently to ensure they don't get stuck!) and a short piece of timber that I press down on the track. I also ended up gluing about half a length at a time. The first part of the second half has glue applied by putting some glue of a sliver of paper, then sliding this under the track. Make sure that the rail joiner to the next section is attached at the same time - trying to slide it under the end of already-laid track takes some serious excavation work.
Laying and aligning double track is tricky - I judged it by eye on the curves (my usual approach in N), and pressed the edge of the track up against a piece of straight timber for the straight sections. This worked well enough with the straights, but the curves aren't as smooth and parallel as I would have hoped - the by-eye technique is compromised by the short setting time of the glue. If I had to do it again, I would make custom semi-circular templates out of plywood and handle them the same way as the straights. I have chosen a centre-to-centre track spacing of 10mm instead of the sectional track's 12.5mm. This looks better and still gives adequate clearance between tracks. The width of the trains themselves is slightly less than the width of the sleepers, plus a bit of overhang on curves.
Standard Xuron cutters work very well with the T gauge track - I haven't even had to file the ends of the rails.
As expected, putting rail joiners on curves is problematic - much easier to place them on straight sections even if it involves using shorter sections of track to make things line up. The rail joiners aren't always up to the job of keeping the track properly aligned, especially on curves, but using a screwdriver to squeeze the fishplates tight to the track and some careful cleanup with a rat-tail file solves that problem. In one case I had to use a blob of solder to fill a gap and then shape it to the rail profile with knife and file (fortunately this was in a tunnel). If you can run your finger over the joint and it feels smooth, then all is well. Laying the track on a hot day is always good insurance against rail expansion.
Power feeds to the track are done through the rail joiners. These are actually small sections of 6 sleepers with two brass fishplates attached. A bit of work with a knife on the underside gives access to each fishplate, and each has a small brass tab that can then be bent down and soldered to. The wires are passed through a largish hole in the trackbed under each joiner section. For reliability, I am putting two power feeds in each section, on the last joiner at each end.
I provided section breaks by cutting the flexi track with the Xuron cutters after it had been laid. Care is required, and I only did this on straight sections (minimum stress) and ensure that there is more glue than usual in the vicinity. I had to make two closely-spaced cuts to get a clean gap, and even then the rails bent slightly and had to be straightened carefully with a pair of pliers. The gap is then filled with a piece of plasticard in a blob of superglue, then trimmed to the rail profile with a knife and file. All my breaks are in one rail only - I would not recommend cutting both rails near the same point. Alas, there really isn't enough room to get a Dremel cutting disc in without damage, especially with the way it reacts to steel rail. I am glad I only needed four gaps.
The layout uses flexi track throughout, and learning how to work with the T gauge track was a new experience. The flexi track is harder to handle than the N gauge equivalents. As soon as a length is removed from its plastic tube, it tends to twist like a corkscrew. When bending it around sharper curves, the twist becomes even more pronounced. As a result, the track really has to be firmly secured to the baseboard. It is also quite delicate - rough handling can pop the rails out of the chairs - I did this to the first length, but took more care and there was no trouble with the rest of them.
After a few small experiments, I settled on using superglue to attach the track directly to the plywood trackbed. You only have 15-30 seconds before this sets, so it needs to be bent and fit-checked first. I hold the track down with some combination of fingers (moving them frequently to ensure they don't get stuck!) and a short piece of timber that I press down on the track. I also ended up gluing about half a length at a time. The first part of the second half has glue applied by putting some glue of a sliver of paper, then sliding this under the track. Make sure that the rail joiner to the next section is attached at the same time - trying to slide it under the end of already-laid track takes some serious excavation work.
Laying and aligning double track is tricky - I judged it by eye on the curves (my usual approach in N), and pressed the edge of the track up against a piece of straight timber for the straight sections. This worked well enough with the straights, but the curves aren't as smooth and parallel as I would have hoped - the by-eye technique is compromised by the short setting time of the glue. If I had to do it again, I would make custom semi-circular templates out of plywood and handle them the same way as the straights. I have chosen a centre-to-centre track spacing of 10mm instead of the sectional track's 12.5mm. This looks better and still gives adequate clearance between tracks. The width of the trains themselves is slightly less than the width of the sleepers, plus a bit of overhang on curves.
Standard Xuron cutters work very well with the T gauge track - I haven't even had to file the ends of the rails.
As expected, putting rail joiners on curves is problematic - much easier to place them on straight sections even if it involves using shorter sections of track to make things line up. The rail joiners aren't always up to the job of keeping the track properly aligned, especially on curves, but using a screwdriver to squeeze the fishplates tight to the track and some careful cleanup with a rat-tail file solves that problem. In one case I had to use a blob of solder to fill a gap and then shape it to the rail profile with knife and file (fortunately this was in a tunnel). If you can run your finger over the joint and it feels smooth, then all is well. Laying the track on a hot day is always good insurance against rail expansion.
Power feeds to the track are done through the rail joiners. These are actually small sections of 6 sleepers with two brass fishplates attached. A bit of work with a knife on the underside gives access to each fishplate, and each has a small brass tab that can then be bent down and soldered to. The wires are passed through a largish hole in the trackbed under each joiner section. For reliability, I am putting two power feeds in each section, on the last joiner at each end.
I provided section breaks by cutting the flexi track with the Xuron cutters after it had been laid. Care is required, and I only did this on straight sections (minimum stress) and ensure that there is more glue than usual in the vicinity. I had to make two closely-spaced cuts to get a clean gap, and even then the rails bent slightly and had to be straightened carefully with a pair of pliers. The gap is then filled with a piece of plasticard in a blob of superglue, then trimmed to the rail profile with a knife and file. All my breaks are in one rail only - I would not recommend cutting both rails near the same point. Alas, there really isn't enough room to get a Dremel cutting disc in without damage, especially with the way it reacts to steel rail. I am glad I only needed four gaps.
Scenery
The station platforms use 3mm ply strips on a 1mm card base to get the correct 4mm height (2mm for the flex track, then 2mm (3 feet) above rail height). The viaduct and tunnel mouths are made of timber with stone-embossed plasticard glued on and painted.
The current backscene is a Gaugemaster product that I chose not to use on an earlier layout, cut out and stuck against a painted sky. The bottom half or so of the backscene visible in the early pictures is obscured by the real scenery. By the time the main scenery was finished, the backscene ended up looking ragged and dark, and so is scheduled for replacement before the layout's next showing. The replacement is likely to be a panorama taken from Google Earth and colour-matched to the existing scenery.
The main scenery was constructed using traditional techniques: the basic outline done with plywood ribs and the surface support with heavy corrugated cardboard (from big cardboard boxes). Plaster bandage went over the top, and gaps filled with normal domestic gap filler. Everything was given a coat of paint using sample pots of standard indoor acrylic paint. Ground cover was done using standard fine grass flock (mainly burnt and yellow grass). Care was taken to avoid large areas of uniform colour.
The track was painted using anonymous grungy brown acrylics, then ballasted using the fine ballast from tgauge.com using a 25-33% mix of PVA glue and water with the usual drop of washing-up liquid. The most useful tool here was a brush with a width equal to the 3mm track gauge. This could simply be swept along the track, with a few stray hairs cleaning the outer ends of the sleepers at the same time. The critical thing here was thoroughly cleaning the track afterwards - T gauge is far more sensitive to glue and paint residues than the larger scales. I found that running a finger along the track to check worked best - that tested both the rail tops and the inner surfaces.
The two large hills at the ends are removable to give access to the tracks below. These are held in place for transport with 1/4" bolts and wingnuts, with foam padding (disguised to look like hedges) concealing the joins.
The buildings are very simple. I looked for suitable pictures on the web, then used Paint and GIMP to effectively make and print my own DIY paper kits. The paper was wrapped around and glued to blocks of balsa. Roofs are from Plastruct L-girder with chimneys made from narrow styrene strip.
The castle is a clay mantlepiece ornament - a 1:600 model of Conwy Castle by Lilliput Lane.
The concrete footbridge is just Plastruct U-channel cut and glued. Station lights are Peco track pins. Bus shelters are thin styrene glued to two standard office staples. Hedges are thin strips of foam rubber. Fences are railings for 1:450 model ships, while the people are pre-painted 1:400 brass etchings of airline passengers (both from a Czech company called Eduard).
The station platforms use 3mm ply strips on a 1mm card base to get the correct 4mm height (2mm for the flex track, then 2mm (3 feet) above rail height). The viaduct and tunnel mouths are made of timber with stone-embossed plasticard glued on and painted.
The current backscene is a Gaugemaster product that I chose not to use on an earlier layout, cut out and stuck against a painted sky. The bottom half or so of the backscene visible in the early pictures is obscured by the real scenery. By the time the main scenery was finished, the backscene ended up looking ragged and dark, and so is scheduled for replacement before the layout's next showing. The replacement is likely to be a panorama taken from Google Earth and colour-matched to the existing scenery.
The main scenery was constructed using traditional techniques: the basic outline done with plywood ribs and the surface support with heavy corrugated cardboard (from big cardboard boxes). Plaster bandage went over the top, and gaps filled with normal domestic gap filler. Everything was given a coat of paint using sample pots of standard indoor acrylic paint. Ground cover was done using standard fine grass flock (mainly burnt and yellow grass). Care was taken to avoid large areas of uniform colour.
The track was painted using anonymous grungy brown acrylics, then ballasted using the fine ballast from tgauge.com using a 25-33% mix of PVA glue and water with the usual drop of washing-up liquid. The most useful tool here was a brush with a width equal to the 3mm track gauge. This could simply be swept along the track, with a few stray hairs cleaning the outer ends of the sleepers at the same time. The critical thing here was thoroughly cleaning the track afterwards - T gauge is far more sensitive to glue and paint residues than the larger scales. I found that running a finger along the track to check worked best - that tested both the rail tops and the inner surfaces.
The two large hills at the ends are removable to give access to the tracks below. These are held in place for transport with 1/4" bolts and wingnuts, with foam padding (disguised to look like hedges) concealing the joins.
The buildings are very simple. I looked for suitable pictures on the web, then used Paint and GIMP to effectively make and print my own DIY paper kits. The paper was wrapped around and glued to blocks of balsa. Roofs are from Plastruct L-girder with chimneys made from narrow styrene strip.
The castle is a clay mantlepiece ornament - a 1:600 model of Conwy Castle by Lilliput Lane.
The concrete footbridge is just Plastruct U-channel cut and glued. Station lights are Peco track pins. Bus shelters are thin styrene glued to two standard office staples. Hedges are thin strips of foam rubber. Fences are railings for 1:450 model ships, while the people are pre-painted 1:400 brass etchings of airline passengers (both from a Czech company called Eduard).