Get up/pick up steam
Definition 1 of 2
Pro Tip 1/3Increasing Activity
Use it when something is gradually becoming more intense or active. 
As the evening progressed, the party really started to pick up steam.
Pro Tip 2/3Gaining Support
Ideal for describing something that is receiving more backing or popularity over time. 
Her environmental initiative is picking up steam among local communities.
Pro Tip 3/3Metaphorical Use
It's a metaphor from when steam engines build power, but now refers beyond literal speed or power. 
The new software update is picking up steam due to its user-friendly features.