Mark,
I may be a little late to this talk about the roads , but I don't understand what you are trying to accomplish by connecting the two roads. An extremely steep street would be something more in line with Lombard street in San Francisco. Otherwise it looks like you introducing a helper grade for automobile traffic.
I'm thinking of 2 alternatives.
1. Treat the upper and lower streets as separate scenes. Put up a guardrail fence along the upper road to prevent wipe outs.
2. If you want to connect them then make the incline as long as possible. Try to make it more realistic and believable.
Remember it's your Railroad, this is just a suggestion.
