When I was testing it I started some random freight service in Gemünden on MSB, but for example in Nahverkehr Dresden most freights starting in Dresden should easily show you that too.
Well, pumping up the brake pipe logically would take a lot longer than emptying it. Pumping up 200 m of pipe to 5 newtons ought to take more than a trivial amount of time.
BTW, a nice little detail on the El Cajon model SD40- haven't seen this on any other loco: when your consist goes around a curve you can see the airflow gauge flicker; it's effectively zero but the movement of the hoses is still creating "ripples" in the BP.
There is a mod that enables BR 101 substitution on freight trains across the board, but I believe in BRO the BR 101 substitutes also by default.
It depends what the initial condition is. Pumping up the main reservoir line and especially the auxiliary reservoirs (usually 100-200 L on coaches) will absolutely take 5 minutes, at least for a decently long train. Charging the brake pipe after a dump, but with charged auxiliary reservoirs, will be significantly faster though since you have the main reservoir line (passenger coaches) to feed the brake pipe and the brake pipe volume is much smaller than the aux reservoirs. UIC brake pipes are 1.25 inches in diameter and the length of the brake pipe is something like length + width since it goes to the side of the body and back, so for a IC coach that's a little below 30 meters. That gives a volume of 22 L so only 10-20% of the auxiliary reservoir.
The BR101 is not really setup to realistically drive freight trains at the moment (that might change in the future but it might not, there's a lot of things that would need to be implemented). For example the brake mode is fixed "R" which is not suitable for freight trains. EDIT: Also compare the time it takes to charge the BP on freight trains with the BR101, against for example the BR185. If the BR185 is equally slow it might be a wagon issue.
That's an issue with a lot of the DRA fright formations. On start up the are completely empty. HL manometer jumps up to 5bar pretty fast, but it still takes 5 - 7 mins for the brakes to release. The HBL manometer indicates that air is still pumped into the train. You can see the issue at the start of this video:
It's not that the train starts without air, I'm pretty sure the rear starts at around 3.4 bar, but the DRA wagons are very slow to charge. This issue was somewhat resolved (not perfectly) on KWG. I made some tweaks to all the wagons used there and the BR185. However, the BR185 suffers from an issue (same as the DRA version) where the automatic overcharge is too weak so the brake pipe only goes up to about 4.9 when releasing the brakes and then very slowly rises to 5.0 bar. IRL it would jump up to around 5.1-5.2 bar automatically which speeds up release. The BR101 is much better in this regard. It overcharges more, by itself, so it probably suffers less from this issue with freight wagons. Still, you probably should at least expect 2 minutes to recharge the brake pipe from ~ 3.4 bar.
Fair enough, could be that way too. I'd totally be fine with two minutes, just the 7mins the way it's shown ingame is pretty long for just charging the BP.