You are looking at the holy grail. Well, sort of anyway. I've have known for years that fishermen have access to lead free weights intended to replace the traditional shot. This sounds like just the thing for the inside of locomotive boilers, wagons and other places where I need the vehicle to be heavier. Even model boats can benefit from this occasionally.
Needless to say I have asked in fishing shops and they just look at me like I'm stupid. This has been going on for a long while. To be honest I'd given up on the stuff. Then at a car boot sale of all places I find a box of the stuff at 20p a packet. Result !
The weight is a sort of heavy putty and weighs around 20 grammes. It's very flexible and sticky. I've not tried eating it but according to the packet I won't die horribly, or at least not if I'm a swan or other form of bird life. Mind you they can eat some pretty horrible stuff and not peg out so perhaps that isn't a guide.
Needless to say a quick Google is useless. Evode Ltd is now part of the Bostick group and there is still no sign of the stuff anywhere. Looks like I need a trip back to the boot sale. If I get enough, maybe I can make my fortune flogging it to railway modellers !