Sunday, May 23, 2010

Making a point...

Well now that basic trackwork is behind us, I guess we should look at building a turnout. There are numerous articles on the subject and everyone pretty well has their own ideas, so I will just describe the basics of what we did to build ours.

First thing that needed to be achieved was to build a frog. Not to many detailed P87 ones available particularly to NSW standards. First a copy of a number 6 point was used which Keiran Ryan had drawn up with correct sleeper spacing and alignment. Or use Greg Edwards data sheets. This was then white glued to a small sheet of ply and left to dry. Next some copper clad circuit board was fixed down and special shapes brass soldered as cross members. Now using the paper template as a guide the straight stock rail was soldered down. From here on track gauges are used in case there are any irregularities in the paper copy. Plus without correct guages that 0.58mm flangeway is a little hard on the eyes. Rather then me go into all the technical specification a down-loadable pdf is available here.  The frog which has been tested and all working nicely, is cut from the jig and nut and bolt detail added.

That was a fairly time consuming job but the best part is that now we have an assembled frog, ready to be sent to the caster so we have lots of little drop in number six frogs. We couldn't seem to locate anyone to cast these in nickel silver so we had them cast in brass and in silver by Apecs Investment Castings. The silver won out and were used. From memory I think it cost about $40 for the molding and then $6 for each casting.
To Be Continued...


  1. Hi Andrew,
    I read with interest your process of creating your on frog - good job. I am building a VR prototype frog to P87 and have a couple of questions for you.
    Did make any allowance for the shrinkage, is it insignificant 3% etc
    Why did choice silver over white bronze.
    And with silver being soft have you noticed any excessive wear. Regards damian

  2. Damian,
    We didn't make any allowances for shrinkage and the cast measures out the same as the master.
    We did three different materials as a test , silver, brass and bronze. The bronze really didn't cast well and the colour like brass was not very good.
    The silver is soft and we have been watching for wear but to this date have not found any.