QCAD - Lancashire & Yorkshire Locomotives

Discussion in 'CAD Corner' started by Lancastrian, 2 November 2019.

  1. Lancastrian

    Lancastrian Western Thunderer

    This is where I currently am with the Hughes Compound.

    The top drawing shows the frames as set for S7, with the wheelsets drawn to prototype dimensions. Once again, I'm getting to the stage of running out of copies of the original drawings to work from, so will not be able to progress too much further, so I'll return to the Baltic Tank or the Belpaire firebox A class.

  2. Lancastrian

    Lancastrian Western Thunderer

    Scale drawing showing clearances for a 6' (1828mm) radius curve on the inside rail and frame spacing for S7.

    Axle 2 will have no side-play as that will have the inside cranks etc and axle 4 will have the gearbox and minimal side-play. I'll have to make some compromises when it comes to the outside connecting rods, as clearances are rather tight.


    This is what it should eventually look like. As can be seen, hopefully, the leading coupling rods are offset, and this style was used on the Stanier 8F.


  3. Lancastrian

    Lancastrian Western Thunderer

    I've only just noticed in the above photograph that the outside (HP) connecting rods have a section in the middle where there is no fluting. Would this be to allow the rods to bend in the event of a problem ? I can't say I've seen this before on a locomotive.

    Last edited: 10 October 2021
    Osgood likes this.
  4. Lancastrian

    Lancastrian Western Thunderer

  5. Lancastrian

    Lancastrian Western Thunderer

    It has been a while since I've updated this thread as my attention turned to other things. However, I have been getting to grips with Fusion 360 for 3D CAD work, specifically for the 0-8-0 Compound, with advice and help from mickoo of this parish, Mike Hopkins and Nikki Wilkes.

    Firstly, the cranks.

    Then it was the turn of the coupling rods, which will also fit the small and large boiler 0-8-0 classes.

    With some help from a GOG member, the inside connecting rod was drawn, which is also common to some of the other 0-8-0's depending on which Lot number they were built to.

    The crossheads for the inside low pressure cylinders were more complex.

    My attention then moved to the outside HP cylinder connecting rods.

    Closely followed by the outside HP cylinder crossheads.

    The outside slidebar brackets were then drawn.

    Steam admission to the outside HP cylinders is derived from rocking shafts connected to the radius rods for the LP cylinder valves.

    These do of course require mounting brackets.

    The HP cylinder front covers have also been completed.

    At the moment I am still working on the linkage for an intercepting valve. This allowed the locomotives to start as simples when in full gear, and automatically changing over to compound when the cut off was adjusted, similar to the Linder system originated on the Saxon State Rly.

  6. Lancastrian

    Lancastrian Western Thunderer

    The LP cylinder covers are now done too. A lot simpler !

    Ian_T, Duncan Chandler and adrian like this.
  7. simond

    simond Western Thunderer

    Lovely work!

    Will you 3D print and then investment cast in brass?
  8. Lancastrian

    Lancastrian Western Thunderer

    Hi Simon,

    At the moment I am toying with investment casting for those items that will require it, but using resin prints for items such as the cylinder covers, for example.

    The intercepting valve linkages could be cast, but do they need to be ? The activating rod will in all likelihood be etched, and the parts don't need to work, so they are in essence cosmetic. Even if I made the reversing gear work, those parts could stay resin/etched.

    Items such as the slidebar brackets, connecting rods etc would be cast in either brass or nickel-silver depending on final finish.

    simond likes this.
  9. Osgood

    Osgood Western Thunderer

    The partial lack of web on the o/s connecting rods as seen in the photo seems most peculiar to me - must reduce strength very significantly.
    simond likes this.
  10. Lancastrian

    Lancastrian Western Thunderer


    It is an interesting detail, though the drawings do not depict it, and I have seen other photos where the connecting rod does not have a section cut out.

  11. simond

    simond Western Thunderer

    I’d think stiffness would be a bigger issue than strength.