Here is my pouring cart and lifting crane. Also shown are my lifting tongs. The pouring cart started as a two-person pouring shank, which I modified. It will handle a #30 crucible, and it has adjustable fingers to allow a larger crucible size (a #30 is probably as large a crucible as I will use). A #30 will hold about 86 lbs of iron, and the crucible itself weighs almost 20 lbs. There is a retainer that slides over the top of the crucible to prevent it from falling out of the shank when pouring. I used large wheels since I was not sure if I would need to work in the grass or not. I discarded the rubber tires since they will melt and otherwise go flat all the time. I have tested the cart with 150 lbs of weight, and it still moves and handles easily. The crane is a bit unstable, although it does work if everything is balanced correctly and the stops are set correctly. I am going to modify the crane to attach it to the furnace frame as Denis has done, in order to stabilize it. I used standard lifting tongs, which required a somewhat tall crane mast. I hate to cut off my lifting tongs since I sometimes use them manually without the crane. I guess I could make a short custom lifting tong. The tongs have a notched bar towards the top of the handles that swings down horizontally and locks the tongs in place.
Pat, For a long time I was terrified at the thought of putting pump up wheels on my pouring trolley, so I used solid lawn mover wheels. It worked great until I got the bright idea to mount a video camera on my pouring trolley. The solid wheels transmitted a lot of vibrations when moving to the camera. I removed them and put on pump wheels from a pram. Have a look at my video when disaster strikes at the three minute mark and yes the wheels still hold air pressure today. If I were you I would put the tires back on again.