When Caps are marked for 10 V, they should be used at 10V + estimated 30%...but not for more! Take care your DCC voltage is max 12.5 V at the track or just use 16V caps. If not the caps tend to explode! You can see the remainder of the exploded cap, the dents on the tender body and chassis. With 12V input voltage to the digital booster you should be safe, but better check the manual and test the track voltage. By the way the Zimo decoder survived this incident without any damage. Probably RRR should switch to tender made from brass or nickel silver - they should be more resitant to explosions...:-))