I have to add different data points to what Jim is experiencing in installing EM13 (or the like) decoders into Kato passenger trains, Shinkansen or no Shinkansen. First of all, almost all Kato passenger trains released over the pass couple of years use this type of decoders and their installation by opening a hatch on the bottom of the motor car. Maybe they have changed the design over the years but I have not seen any different designs in the wild. I realize there's always an exception to the rule.
Yes, you have to remove one truck for full access but that can be done in less than 5 seconds with the rounded corner of a credit card or hotel room key. Installing it back is just a matter of lining everything up and snapping it back in with a gentle push. The time it takes me to install the trifecta of decoders is less than the time it takes me to program them for operations!
I have installed dozens of EM13 (although I have never done the ESU sound equipped equivalent but I would assume it's the same) on my own trains as well as for others with have had zero EM13 failures. The only "mistake" you can really do is flip the decoder incorrectly when installing. Other than that, you just basically slide it in until it "bottoms" out. If you take a look at the contact traces on the decoder on both sides, you'll see they are HUGE. So I don't understand how you can misconnect the four large contacts, two on the top and two on the bottom.
