In pitch black you are dumped in the cab & the brakes are not set, you immediately begin to roll back on the 1.5% gradient, I have to quickly get out & set the handbrake to prevent an accident! Again this bug has existed since launch of CRR! Please sort this, it's not on to leave issues like this unattended to for a DLC you charge £24.99 for!
Yes, it's a noted bug. But as to amelioration... I would suggest instead of the parking brake (which isn't intended to stop a train, only hold an already-stopped locomotive), which takes way too much time, use an easier approach: as soon as you get control turn on the cab light (so you can see what you're doing), set the MU-2A valve to Lead, and pull the loco brake handle to 100%. That should stop you post haste.
I don't know if there's a controller button, but try the same one that turns on your flashlight in foot mode (on PC they are both the L key). If you want to grope for it in the dark, it's above the window to your right.
As solicitr said, it‘s [L] on an external keyboard. If you don‘t have one, you either need to search around for it or maybe stand up and use your flashlight to find the MU-2A valve.
I watched some of Matt's breaking tutorial last night & he chose the McClure Shifter Pt1 & the same happened, however blink & you missed him sort the problem!