For 7 1/4" gauge railways there are more choices with several custom profiles in alunminium on the market or custom produced profiles by clubs or individuals. The guidence for 7 1/4" gauge is still the same although if you are running engines that weigh in at over a ton, you are more likely to run on steel track.

The cost of steel and aluminium are very close so usually it is other factors that influence the choice.

STEEL - Profiled rail - 21mm from MRSC

Advantages

Very strong, needs less support (less sleepers if required)
Can be welded for rigidity or for example constructing crossovers
Lower expansion rate. Half that of Aluminium
Good impact resistance - hard wearing - especially good for areas such as point blades and frogs.

Disadvantages

Rusts - with constant running isn't really a problem
Hard to bend. Good for staying in shape once bent but is hard bending by hand. Can be bought from Miniature Railway Supply Company pre curved but for flexibility I would recommend one of our rail benders
Heavy - not very good for portable track as you will only be able to lift 3 panels at a time.
Hard - may save rail from excessive wear but this may be taken out on your rolling stock.

ALUMINIUM - 16mm and 21mm

Advantages

Easy to bend - Good for laying, bad for un supported track
Light weight - good for portable track - I can easily pick up 15m
Doesn't rust
Soft material - doesn't wear the wheels - very important if you have a £8k steam engine

Disadvantages

Soft material - With sharp corners sign of ware show quite quickly, also derailments can damage track.
Point blades and frogs made from aluminum can show signs of wear very quickly.
High expansion rate. Hot sunny days can see track snaking as it expands. - Must allow for expansion at joints.

Left - Aluminium rail - this piece was nearly 8 years old in use on our bottom curve which is an 11 foot radius. I would consider that we are reasonably heavy users so I don't think this wear is unacceptable.
We could have re gauged the track and carried on using the rail but decided to replace it with steel.

The rail won't we wasted as it will be straightened, turned and used in our new siding.

Suppliers

PNP Railways - Paul Norman Plastics - Aluminium rail + Plastic sleepers, chairs etc. 16mm and 21mm aluminium alloy

Miniature Railway Supply Company (MRSC)- steel and aluminium alloy, flat bottom profile 21mm high + 16mm aluminium alloy

Cromar White - 16mm high Alloy

Maxitrak - 16mm high profile aluminium alloy

Bar Track

While many clubs use bar track there can be problems. The running edge of the bar needs to be rounded or else it can easily cause excessive damage to the wheels. In the garden environment with tighter corners the sharp edge can destroy wheels in quite a short time.

The wheels on the right were off a Trojan which had been run on a garden track constructed from steel bar. It had tight radius corners which caused excessive wear on the wheels. These wheels have had less than 6 months of occasional running.

For club running with large sweeping curves, the chances of marking the wheel flange is greatly reduced.

Sleepers

1) Timber roof battern - 225mm long - 32mm x 25mm - Timber is tanalised but we also immersed them in creosote(or new alternative) for at least a fortnight. Rail fixed with 3/4" x 8 pan head screws with M4 penny washers.

2) Aluminium - Jubilee rail - copy of the narrow gauge sleeper for temporary track ie used on peat bog systems. Advantage of not rotting but major diadvantage is that the track sits on top of the ballast and the track is prone to movement. Only for 16mm rail.

3) Timber battern as per number 1 but with plastic chairs as supplied by PNP Railways.

4) PNP Railways plastic sleeper. Offers pre set gauge and possibility of gauge widening + rot resistant.

5) NOT SHOWN - PNP railways produce a clip together system in 5" and 7 1/4" gauge. Panels can be assembled in a matter of minutes. A major plus given a panel can take up to an hour to screw together.

5" Gauge Sleeper Spacing


	6 sleepers per metre Temporary use or hidden sidings/sheds	9 sleepers per metre. This is what we found looked good.	12 sleepers per metre Just too much although near standard gauge track standards

Hardwood vs Softwood

Many people have written on the subject of sleepers and quite a few have written off softwood as a short term investment. The picture on the left is of sleepers which have been down for 8 years. There is no sign of rot and still have many years of life yet.

In comparison we have seen hardwood supplied with a point kit degrade quite badly to the point where they needed to be replace. It didn't help that they came with live woodworm in.

Recycled Plastic

Recycled plastic sleepers have many advantages but one major disavantage. In the sun they can curl. Do not use on points as the distortion in the longer sleepers can affect the operation of the point.

Thermal Expansion

Why should this bother me?

Below is a table showing the thermal expansion of three materials. Concrete has been inlcuded as a comparision.

Product	Linear Temperature Expansion Coefficient
Product	(m/m.^oC x 10^-6)	(in/in.^oF x 10^-6)
Aluminium	22.2	12.3
Concrete	14.5	8.0
Steel	13.0	7.3

Column two shows the expansion rate per degree in temperature rise. If for example we say that it could easily get to -10^oC in the winter and easily get to 50^oC in the summer (if the track sits in the summer sun all day) we will get a temperature range of 60^oC.

Therefore a

2.5m aluminium track panel will be 2.5 x 22.2 x 10^-6 x 60 = 0.0033m
2.5m steel track panel will be 2.5 x 13 x 10^-6 x 60 = 0.00195m

So for a track in the sun you will need to leave movement for 3.3mm for aluminium and 1.95mm for steel. Yes movement.

Fishplates should not be bolted tight - use nylocs or double nuts.
Regularly grease or oil. This also helps reduce electrolytic action that can lock up fishplates and stop the rail moving.
Over drill the holes in the rail - use 5 or 6mm drill bit for 4mm bolts.
If laying rail on a very hot day the rails should butt each other. At 20^oC the rails should be mid way through their movement.

Don't worry too much. If you get it wrong the rail will find its own way to expand. On corners it will push out and on long straights it can even lift the track into the air. Over a period of time you will soon learn where you need to allow for more expansion.

Above - This is the inside of a curve and taken at 3pm on a sunny June day. The gap between the ballast has been left as the rail pushes out the curve as we had not allowed for expansion in the fish plates.

Restaining the sleepers can allow the rail to slide on the sleepers and the expansion to be taken up in the gaps left in the fish plates. It is not recommended to try and totally restain the rail as you will find at some place the rail will find a way to move to accommodate the expansion.

On the full sized railways welded sections are often laid stretched so the any expansion can be taken up in the spring of the steel. With most miniature rail supplied in 2.5m or 3m legnths I think you would be hard pushed to lay rail pre tensioned.

Points

Don't believe there is anything such as a standard point.

The picture above is of one of our standard 5" gauge points. Over a peroid of years I have noticed that there is no such thing as a "standard pair of points".


Sneafell - single bladed point.	Another single bladed point at Chatham Docks. When set to go left the back of the point blade acts as a check rail and guides the wheel set left. The right point blade is replaced by a frog.
	Model Points. Definately not trailable.
Point blade with a diffrence. This is part of the small tramway at Milestones Museum.

Another single bladed point but this time the rail pivots so there is no frog.	Cast point blade and frog units. Centre pieces are lifted and put back down to change the points and frog direction.These are set in the court yard of Penryn Castle

A set of points at Audley End Model Engineering Club. These points do not have traditional frogs but a sytem of mini blades and pivotting rails. The big advantage is there is no open gaps for wheels to drop down. Incredibly smooth to drive across. The disadvantage is that they are not trailable so must be set in the correct direction when approaching from the rear.
	Left - a 3 rail model railway system at Chelmsford Show. The centre part rotates making the centre rail become the left running rail. Not sure how the electrics work.

Why are they so expensive? The simple answer is that they are complex and complicated. Our points are made up from 168 parts and takes the best part of a day to assemble.

From experience we found that cast aluminium frogs fail quite quickly (medium to heavy use) as the aluminium is not strong enough to cope with the impact of the wheels. To combat this we use a laser cut steel frog. Also on the market are cast iron frogs which also cope better. That said and done, the aluminium frogs are not expensive and can easily be replaced.

Notes

The check rails are to protect the frog and stop the wheels straying up the wrong side. Make sure they are located correctly and not just bolted on to the adjacent sleepers.
The curve on the turn out has more than one radius
For 5" gauge check rails need 6mm clearence. Point blades also need to clear at least this
For your first point - buy ready made. Kits may sound cheap but without reference to how it should go you will easily lose a couple of days constantly tweaking it to get it right.

Next Stage- Curves and Gradients