I'm not a paint expert by any measure, but I've learned that trying to match a color using off-the-shelf products is challenging at best.
On a recent project (see below) I used "Rust-Oleum 334043 Painter's Touch 2X Ultra Cover Spray Paint, Gloss Real Orange" - readily available at Menards, Lowe's, Home Depot, etc. It's very orange, but I don't have a "Lionel orange" piece to compare it against. Any color looks different in person vs. a photo, and comparisons to an existing piece are affected by the age of the finish.
A can costs under $8, so it's possible to experiment on a test piece. If an exact match is a requirement, I'd suggest contacting a vendor of toy train paint such as Henning's. However, I don't think they sell rattle cans, so using their paint is likely to require using an airbrush.