Fixing external track

[Greg Elmassian]

One answer to one question, why not screw track down and unscrew if there is a problem.

The reason not to do this is normally the rail is pulled from the "spikes" that hold the rail in place and often the ties are damaged.

I've seen lots of ruined track where it just was discarded. A wealthy gentleman near me had narrow concrete curbs laid to place LGB track. It was in a sloping area that had several "putting greens". The area had been recently graded, and there was no reinforcing bars connecting the concrete "curbs" that the track was laid on.

As time went on, the concrete settled, and the track was screwed down every section (using standard LGB sectional track). After a few years, 40% of the track was damaged to the point that rails were completely out of the ties, or gauge was bad enough to cause derailments.

To make matters worse, they had removed the screws through the ties into the concrete and put glue over several ties, so instead of just ripping out one tie (the one with the screw) 3-4 ties were pulled away from the rail, and now even more issues.

So, trying it to see if it does not work needs attention to change before the track is damaged. Many people do not catch the situation soon enough.

Greg

 

[craigwrdouglas2]

We don't get the extremes of temperature in the north of the UK, but the track has been down for 15 years, with a breeze block track bed, with some parts on upvc that was left over from a double glazing company. The track is screwed into place with rigid brass clips and then ballast on top.

We put the track in place in the summer, when the track is approximately at it's warmest and liberally applied the graphite grease between joints.

When the track cools in winter it can gap slightly, but I'm usually in doors by the time that happens.

All the wood that we did use in the trackbed rotted and warped or sunk within a few years [3-5] so was replaced with either concrete or upvc.

Upvc, strips sided with metal salvaged from a old greenhouse, then ballasted worked particularly well for long bridged areas, which make up the rack railway section of the railway.

 

[Paul M]

We don't get the extremes of temperature in the north of the UK,

That is the point, here in Britain we tend not to have a huge range of temperatures as Australia or America experience. Trial and error as Greg said is the way to go. I've pinned the curves of my flexi-track, but left the straights floating, any expansion causes the unpinned parts to flex slightly

 

[Fred2179G]

While ballasting is a slow process so is mixing and laying concrete

I haven't noticed anyone mention that maintenance involved with ballasted track. Mine, in a relatively wet area of the USA (Maryland) needed the ballast reworked every spring - the rains washed some away. It was only once a year, but with a big layout it is still a chore.
Concrete has the advantage of (perhaps) not needing the annual re-ballasting. With the track held loosely in place with straps, it should not need much work.

 

[Greg Elmassian]

There's a whole discussion on ballasting...

For example I use coarse ballast, much bigger than prototype, but survives rain and might need work once every year or 2.

If you want prototype size ballast, be prepared to re-do it often... then you get into the similar discussion of gluing or not gluing ballast, just like trying to fix track in place.

Some people succeed with glue most fail... it starts to lock the track in place like trying to screw it down,.

You can go on and on about this.... get your trackwork in place, working well, level and you are way ahead of 50-70 percent of everyone... then go to ballast, my opinion.

Too many people starting out try to get to the end result, and getting track crosslevel right, and kinks out, and eliminating humps and dips takes some learning. The plus side is if you do this, your trains will run perfectly, slap it down, and derailments, and NO FUN.

Greg

 

[LGeoB]

There's a whole discussion on ballasting...

For example I use coarse ballast, much bigger than prototype, but survives rain and might need work once every year or 2.

If you want prototype size ballast, be prepared to re-do it often... then you get into the similar discussion of gluing or not gluing ballast, just like trying to fix track in place.

Some people succeed with glue most fail... it starts to lock the track in place like trying to screw it down,.

You can go on and on about this.... get your trackwork in place, working well, level and you are way ahead of 50-70 percent of everyone... then go to ballast, my opinion.

Too many people starting out try to get to the end result, and getting track crosslevel right, and kinks out, and eliminating humps and dips takes some learning. The plus side is if you do this, your trains will run perfectly, slap it down, and derailments, and NO FUN.

Greg

Same here. The ballast I use is crushed red rock which is coarse is it doesn't get washed away. It is just small enough to fall between the sleepers so I cover the track with it, give the track a waggle, the ballast falls through and locks the track down. Can just about walk on it with little movement.

Geoff

 

[Greg Elmassian]

Yep, same as I use, and has worked out fine the last 10 or so years. Rain and even the hose does not dislodge it.

Greg

 

[Gavin Sowry]

Yep, same as I use, and has worked out fine the last 10 or so years. Rain and even the hose does not dislodge it.

Greg

I use 10mm coarse chip, works well. I considered going the scale ballast route, but figured, correctly, that rain is not to the same scale, and something must give.... and it won't be the water.

 

[maxi-model]

I used to get my "ballast", 6 mm granite chippings, from a local aggregates merchant. I found out from them why the types of chippings were inconsistent in colour visit to visit, year to year - It depended on what the quarries supplying them were blasting and crushing at the time. I now use a standard "horticultural" potting grit supplied by my local garden center. The important bit is that the stones are sharp edged and not the rounded "pebbles" you get in 10 mm gravel. They lock together to form a firm base for the track to lie on. I use plastic or metal lawn edging, to provide a "bund", either side of the track/track formations to stop ballast running away. Using a permeable weed membrane under the track bed ensures good drainage.

I went the way of a floating track on a sharp stone ballasted bed as it was the easiest, quickest and cheapest method. It is also easy to remove/redeploy if you reconfigure your line at some point. Turns out it works well and looks the part too. The only downside is that bits of grit can get in the points/switch blades/flange ways/check rails. Maintenance, apart from cleaning point mechanisms - A little spot repacking in the spring (I use about a 20 kg bags worth) and I am good to go for another season of running. Max

 

[JimmyB]

I haven't noticed anyone mention that maintenance involved with ballasted track. Mine, in a relatively wet area of the USA (Maryland) needed the ballast reworked every spring - the rains washed some away. It was only once a year, but with a big layout it is still a chore.
Concrete has the advantage of (perhaps) not needing the annual re-ballasting. With the track held loosely in place with straps, it should not need much work.

Part of any hobby is maintenance, however you blend the hobby to meet your maintenance needs. If you don‘t maintain your hobbies infrastructure then eventually it will fail.

 

[Madman]

where i live we got temperatures between 25°F(seldom) and 110°F(often enough). (-3 to 45°C)
so even after i went "indoors" i get temperature differences of 60°F. (35°C)

over the decades i noticed an important fact. brass rails expand and retract about 2mm (about a 12th of an inch) per foot between the mentioned temperature extremes.
for a piece of flextrack of 5 foot that is a difference of about 10mm (2/5") in length. - long enough to have straights expand into snake-lines and to retract completely out of the fishplate connectors.
but if laying 1 ft. sectional track sections in moderate temperatures i just need gaps as wide as the thickness of a creditcard between sections to allow for the possible expansions or retractions.
that allows me to fix each piece of track at one extreme to the roadbed. (one nail/screw every foot) result: no wandering of track, no slipping out of fishplates.
(plus a nice clickety-clack from the wheels.)

Which reminds me of what a professor told us in structural steel design. When the railroads started using welded rail, the engineers simply figured in expansion and contraction. So on curves the track would move toward the outward curve in the heat of Summer, then relocate in Winter. He also said that the straights would simply take the forces as a load would do to a steel column.

I have my doubts, but in my own garden railway, I notice the curves are the areas where ballasting needs periodic attention.

 

[Fred2179G]

Part of any hobby is maintenance, however you blend the hobby to meet your maintenance needs. If you don‘t maintain your hobbies infrastructure then eventually it will fail.

My point was that ballasted track will need more maintenance than a concrete, un-ballasted base.

 

[Greg Elmassian]

Sorry, in your post you talk about your maintenance issues with ballast... at the very end you do not make it clear that suddenly you are talking about not using ballast, rather the focus as I read English was a concrete base.

 

[Airbuspilot]

I thought I was asking a fairly simple question, clearly I was wrong. Thanks to you all for your help and suggestions.

I had planned to ask a second question about how to ballast but I don't need to do that now!

Thanks everyone

Robin

 

[Paul M]

It was a simple question, it's just that there's a lot of correct answers

 

[JimmyB]

It was a simple question, it's just that there's a lot of correct answers

And a lot that are NOT wrong, just different, just because one person wouldn't do something a particular way, doesn't make it wrong

 

[Greg Elmassian]

I try to go by what works most often for the most people when suggestions are asked for. There will always be examples that are outside the norm.

I know people who have brass track that never oxidizes, they will swear by it. (this guy apparently lives it the cleanest outdoor environment we have ever seen)

I also have found a person that had his stainless steel track oxidize. (turns out he was hitting the track with mildew spray every 6 months with a corrosive acid).

Stranger stories of success and failure do exist, but they are not the norm.

Greg

 

[Paul M]

And a lot that are NOT wrong, just different, just because one person wouldn't do something a particular way, doesn't make it wrong

Yep, more than one way to skin a cat. Apparently, never actually tried it myself of course

 

[Gerard]

Hello,

Being an engineer i like to contribute to this thread with some ideas about the design of modern prototype train rails.
Stretches of several hundred meters long are welded to each other in a straight line by using Exothermic Welding.
This results in a very smooth noise-less operation of the trains.
About keeping the track in a straight line at the most extreme possible high temperature the following remarks can be made:
1 The problem is the internal pressure force along the track due to the expected max temperature increase and material stiffness.
2 One can calculate the so called minimum "Buckling Length" above which the track will buckle under this force. (This is the same calculation that is done for steel structures in bridges and viaducts)
3 The distance between two sleepers, i guess, must be a lot (factor 4?) smaller than this buckling length, to be on the safe side.
4 Note that all the sleepers connect both rails but that this will not increase the minimum buckling length since both rails can (and probably will?) buckle at the same time in the same direction.
5 The sleepers can generate a transverse friction force prohibiting the buckling process. Since we do not want any movement of the sleepers the shear force taken into account must be a fraction of the max shearforce determined by the weight of the track and the friction coefficient of the bed material. This force can be taken into account in the calculation of the buckling length by adding this force to the bending force of the rail in the buckling calculation.
It would be interesting to make such a calculation for an LGB track to see what it takes to fix it as in the prototype..
First i need some help to check if i overlooked any important aspects in this engineering problem.
So Engineers out there, be my guest!

Gerard

 

[dutchelm]

My track is loose in ballast & needs leveling annually. A friend had his on concrete. He had a bit of subsidence. There was no easy cure for that!