Help wiring LED's. Im building/assembling a kasiners Passenger car kit from about 1949 and want to add LED's. But want to power it through the third rail.

Help wiring LED's. Hey fellow o scale model train enthusiast. I bought an old o scale kasiner vista dome car kit from about 1949 and they never included lights. I’m assembling the kit and going to make it look like my other cars by k-line. They sold these kits without truck and couplers. So I bought them 3 rail Lionel ones on eBay I want to wire it up with these leds DiCUNO 450pcs (5 Colors x 90pcs) 5mm LED Light Emitting Diode Round Assorted Color White/Red/Yellow/Green/Blue Kit Box https://www.amazon.com/dp/B073...oding=UTF8&psc=1 to be honest I don’t know if I wire them to the third rail will it be too much voltage? Do I need a resistor and if so what one. My transformer that I use is MTH 750 but planning on upgrading to the z1000. I don't know if that information is important. Thanks in advance!

Here's a link to me making part for this kit.