In the hud it only shows your curent speed, I suggest adding if you are speeding up or slowing down. Examples of other train sims with this info that I know about: MSTS {Microsoft Train Simulator) and OR (Open Rails) Please and thank you
Change your HUD settings, because Simple HUD (in Accessibilty settings, not in HUD settings) does have a meter indicating acceleration just above the current speed.
OP has a slight history of making random threads like this, think it's just lack of basic understanding of what's on the screen. Have wondered if they are very young or of senior years.......
Then they should fix the accelerometer to show it better or replace it. For, ex speeding up it should have either an icon like this ^ or + (plus sign) and for slowing down V or - (minus sign).