Construction - Phase 1

top

What sort of trackbase?

At that time, there was much debate in my mind (there still is!) as to the best way of constructing a track base. The few people I knew at the time to ask, and the various books I read, all had different ideas on the subject; as I've since discovered thay do on most things!

For the record, these are the thoughts I recorded on the original HLR Web site:

Wooden base supported on posts (wood/drainpipe/...) above ground level.

Immediately ruled out as we wanted a ‘real’ railway running through ‘real’ countryside and not detracting from the garden.

Gravel in shallow trench with ‘floating’ track.

Sounds like the real thing but not sure that I was up to keeping everything flat and level with no 'dog-legs' etc.

Track fixed to concrete base at ground level.

Implied a lot of heavy work and had also heard scare stories about tree roots disturbing foundations; once this method goes out of alignment, it stays that way!

Track on brick/block wall just above ground level.

Maybe some of the same problems as above. To start with, track is mostly at or about ground level, although later, further down the hill, I shall probaly resort to building walls.

Wooden base at ground level.

Deterioration doesn't seem to be a major problem if heavy section treated timber is used. Main problem seems to be going round corners. (And this railway is one big corner!)

Since that time, I've visited Bob Petch's Little Corris Railway and seen how effective a trackbase raised on short wooden posts can be. I've seen that track attached to battens ‘floating’ in gravel is OK on Keith Brown's Chidham Light Railway. And a good solid concrete base works fine too, on - Tony Lee's W&LLR.

But for better or worse, I decided at the time to use a wooden construction at ground level. Probably because I wanted it ‘now’, and perhaps too because it had the advantage that if, in my naïvity, I made serious mistakes in the planning, it would not be too difficult to adjust.

The problem of getting round corners was overcome by cutting boards into sufficiently short lengths. Some old fashioned trigonometry was used to calculate the maximum reasonable length of each piece and the angle to which it should be cut.

Just to be on the safe side, I made lots of full-size cardbard templates before laying into the timber with a circular saw, but at the end of the day a lot was done just by eye! (But the template did ensure that I didn't creep below my notional 4' 6" minimum radius.

top

Method of construction

Before putting it in place, I made sure that the pressure treated 7" by 2" timber had a good coating of wood preservative (belt and braces!) making sure that the cut ends were well soaked. It's still doing fine, with no noticable sign of deterioration. It is quite heavy enough to stay put without actually fixing it down and easily supports itself between joints, although a couple of longer pieces have intermediate supports to be on the safe side.

The timber is joined underneath with short pieces of aluminium angle (actually the roof trusses of an old glasshouse). This had the unforseen but added advantage that, by supporting the trackbase at the joints, none of the timber is actually in direct contact with the ground. The diagram, showing a cross section of this system, should make it clear. It is also fairly easy to get everything level, just by bedding down and adjusting the supporting bricks.

To start with this worked fine, but it soon became impossible to attach the next piece as the screws had to be inserted from the bottom. Not to worry. It was found that, once screwed together, the whole trackbase was very strong and could be lifted in one piece! In fact the circle was made in two pieces, assembled upside down on the lawn and then lifted, with a little help, back into place. On one side of the circle, there was a natural break where the bridge has to be inserted. On the other side, two pieces were attached from above so that they could easily be removed later to change the formation of the railway. (In fact, such plans now constitute what has become known as “The big red herring” (see the Planning page), although this ‘foresight’ might yet prove useful.)

Generally, drainage seemed to be taken care of by fact that the supporting bricks were bedded into gravel. The only place where this proved to be woefully inadequate was in the cutting, where floods were not uncommon. Between each supporting brick, I dug a deep hole and filled it with rubble to act as a sump. We've never had a problem since!

The picture to the right shows a section of the trackbase before it was filled in round the edges with loose stones. Just visible under the far track is one of the joining pieces of aluminium angle. (See also the section to the right of the waterfall in the heading picture.)

top

Track laying

Then came the time to actually lay some track and the question arose as to what sort of track to use. I decided quite early on that I wanted something easy to lay and maintain, so I went the route of plastic-sleepered track. At the time, there were two easily available options: Peco or Tenmille. I seem to remember that the decision to go with Tenmille was made purely on financial grounds, although I don't suppose the difference was that great. However, over the years since it was laid, I've discovered that the difference in quality was fairly great - especially that of the points.

Suffice it to say, that all current track laying is being done with Peco track, although I still have some Tenmille plain track to use up on the main running line; there's no point in struggling to join it to Peco track between every point in a station!

Tenmille track comes as separate lengths of brass rail and packs of sleepers joined together with a web between the sleepers. It's just a matter of sliding the rails into the moulded chairs. A drop of WD-40^® on the rail makes this a whole lot easier! Before assembling, rails were bent to approximately the correct radius simply by gently flexing them as they were pulled through an old rag gripped in the other hand. You soon get the feel of how much pressure to apply. Probably not as accurate as a proper rail bender ang harder work, but nearly as effective.

Having been bent to about the right shape, the track only needed pinning lightly to the prepared trackbase before being ballasted with loose limestone road chippings.

top

Success?

This system of making a trackbase proved quite successful and has been in place for four years now with little sign of deterioration. If I do use the same method again in the future, though, there are one or two lessons learned...

• In places, there was a void left under the wooden trackbase which was not filled by the stones packed down each side. Gradually, these stones have worked their way down and I find I'm regularly having to replace them. Because a gaping hole sometimes appears olongside the trackbase, the ballast is often being washed away. It might have been better to have packed the wooden base all round with gravel in the first place.
• I'd assumed that by using wood, I'd have a good flat surface to work with. This was only partly realised. Despite carefully choosing timber at the wood yard, I still ended up with a few twists which meant that the track needed some packing in places to keep it level. This probably didn't help with the next point.
• Although the track hasn't moved much, many of the pins holding it down have come adrift. This has allowed enough ballast to get underneath the sleepers in places to form noticable undulations. I'm now feeling inclined to screw the track down more firmly, and maybe glue the ballast in place.