I'm experimenting on the test bench: My HO scale rollingstock is working great with Kadee's #308 under-the-track permanent magnet which will be used on my spurs. But now I am experimenting with the #307 electromagnet for use on the mainline. In my experiments, the magnet seems to be underpowered. I can get the cars to uncouple, but the couplers don't open far enough for the delayed action. Like I mentioned, the cars work well with the #308 so I don't think this is a rollingstock/coupler problem. I have a 7 amp DC supply that is adjustable from 8 volts up to 15 volts DC. I started out with 10 volts and gradually cranked it up to 15 volts, but the results were still not up acceptable. At 15 volts, the electromagnet was drawing about 1.5 amps, so this isn't a power supply problem. Is there anyone here who has actually successfully used the #307 electromagnet? I am looking for some first hand advice. Do they work without modification? Or did you make modifications? I have seen an article where more metal was added to the sideplates. Perhaps I can put more turns on the coil? Again, has anyone here successfully used these things without modification?