Thanks for your comments eddie and scrat. We get frost heave in Canada because the temperatures drop well below zero centigrade ( -15 to -20 C) for extended periods of time ( months on end) . This allows the frost to penetrate deep into the ground possibly a foot or more locally and much deeper in o...

Thanks for the reply Mike. The grassy blocks I am familiar with but that is not what I mean by permeable concrete and I am not sure it would be any more suitable for a track bed than plain gravel. It is worth some thought though. Frost proof concrete will still crack from frost heave if water percol...

Yer pays yer money and takes yer choice.
I hope the job came out satisfactorily.

davet

If using a standard slot drill the width of the keyway should be correct for standard key steel or propriatory keys. The centering should be satisfactory if you use the methods described previously carefully. Keys are usually made a light "tap fit" in the shaft and a CLOSE sliding fit in the hub. Be...

The easiest way is to use an edge finder to align the spindle with the edge of the shaft and then index in a distance equal to half the dia of the edge finder plus half of the shaft dia. Alternatively align the slot drill against the shaft using a cigarette paper as a feeler gauge. That is, move the...

Nicrome as used in jet engine combustion chambers is a good choice, if you can get it. I have used this in my Ajax and it does not burn out. A 316 stainless should work and give a reasonable life but even a mild or low carbon steel will work for a time but will suffer from burn out .

Dave T.

Charles, Eddy, In full size practice of course several fudges were resorted to including thin flanges, extra movement in all the axle boxes, (must have given a rough ride), as well as track gauge widening, particularly through low number turnouts. The accuracy of full size drawings to what ran on th...

To technical eh? For a 30ft radius, a rough calculation shows that the offset from the centre line will be about 8mm. The angle of swing of the pony truck will be about 2.75degrees. Turnouts are a bigger problem it would seem. Crow-baring vehicles through a turnout may be prototypical for the LNWR b...

Charles, More thoughts on your carriage. It could be that Francis Webb intended to run these carriages as pairs, close coupled, with the radial wheel sets at either end. This may then allow the lead carriage not only to move more smoothly into the curve but also nudge its mate to a similar accomadat...

If the one end wheel set is described as "Radial" the usual interpretation is that it is guided to slide in radial axle box guides, as in Webb's "Radial tanks". The radius can be approximated by a suitable angle and achieve a similar effect. Choice of the radius is up to the individual in this case ...

For a silver soldered copper boiler a solution of vinegar is quite effective. It is also good for cleaning injector cones and filter type coffee pots. It is best used hot and a commercial 10% acetic acid vinegar from Tesco or other supermarket should do the trick. How a steel boiler will react I am ...

Fritz,

No I did not put any reinforcing into the blocks that I made.

Brent,

Thanks for the information and advice. I intend to use plastic sleepers cut from house deck material, which is avaiable over here.

Dave T.

Thanks for the information Eddie, you are obviously in the business of concrete and your comments will be given careful consideration. One reason I thought that permeable concrete might be suitable was because I made some paving and edging blocks using a small agregate, mixed very dry, just to hold ...

Thanks for the reply Fritz. You, I think, are referring to asphalt which indeed requires a big, hot machine. Permiable concrete is just that, as I understand it, and it has been developed to minimised the run off to storm sewers of precipitation in cities, where large areas are covered, by allowing ...

Has any one ever looked into using permiable concrete as a track bed? This stuff is supposed to let the water drain through and if laid on gravel might provide a nice dry support for the track.

Thanks Alan, very helpful.

Dave T.

Which is the official GL 5 scale factor for reducing full size to miniature? Using 5" gauge vs full size, a factor of .088495" to 1" is correct. Using the often claimed 1/12 full scale for 5" gauge gives .08333" to 1" which scales to 4.75" gauge (US sandard?). So what should we students of scale ope...