David Sim wrote:
Morning all

I'm building a part raised pond - 9' x 6' - hole is dug to 4' & I'm planning
on raising the dges by another 20" or so using railway sleepers. I think new
ones will be better, cleaner & easier to use, but does anyone have any
thoughts on securing them to the ground.

Will a frame of sleepers secured with heavy duty brackets be strong enough
to hold the additional 20" of water?

The sleepers own weight will be more than enough. The water's weight
goes down, not out. My own (8x6x3) pond is 50% above ground and the
frame was made from lengths of 2x2" wood with uprights at 2ft intervals.
I then tacked some thick wire mesh over the inside to add support in
the spaces. Finally I put 1" thick polystyrene insulating sheets all
around the side which was held in place with thick plastic sheeting
stapled to the frame. Strength wise it must be a fraction of the
sleepers but is plenty solid. The outside was "decorated" with fence panels.

--
Andy