Apart from just allowing the train to extend past the platform, as they do in the case of many rural stations in the US, you'll typically want to find a platform network to visually extend a platform, along with extending the platform segment with Move It (Don't stretch a platform segment beyond 128m or it can break). There are a few good resources for creating custom stations, such as Rev0's Railway 2 Guide , a couple others on creating long stations, and if you prefer the video format, several episodes in kjmci's Railway series directly cover custom stations.

Hey, I apologize if this is a dumb question, but how would I find long enough stations for this?