? Are you using two transformers. And if so are they phased together? That could cause a voltage doubling up.
Age is just as likely though. Genral rule of thumb, a bulb lasts half as long burning twice as bright if fed double normal voltage; and half as bright for twice the life at half voltage.
The ceramic type element doesn't cook easy, but nothing lasts forever.
Resistor/fluid elements need fluid not burn up. Don't run them dry.
Before you wright it off, the element tab to bowl/well connection and wire insulation should be checked/cleaned.
If the element IS cooked, and the break is one or two wraps near the solder, a resoldering may work. It would run hotter and make more smoke. The element wire wont hold solder; you have to "encase" the wire in a solder blob and don't pull on it 😉. Lionel wrapped the wire; then encased it.
