When I move away from my locomotive it just stops moving. I found this related issue #1237 mentioning a spike cart or chunk loader, but I am not able to find that item ingame or in any railcraft configs.

You need to learn how minecraft works. When you are away, furnaces will stop cooking, too. Use chunk loaders.

chunk loaders are available from different mods, but in the patron only betas, there are worldspikes (or world anchors in 1.7.10) they will be released in next major release.