Being abreast means being side by side.
abreast - side by side The parade had six drummers marching abreast.
draw abreast = gleichziehen
The origin of abreast is late Middle English: from A- 'in' + breast.
The brass band passed by, marching four abreast.
We have been abreast of this situation for a time now.
I have information here to keep you abreast of the situation, sir.
The president wants to stay abreast of the most recent developments in Libya. OR The protest marchers walked arm-in-arm, five abreast down the street.
Together
uniform
Along side at the same level (think of runners crossing a finishing line "breast to breast" they are abreast of each other and finish at the same time).
it means walking side to side
When a group of people walk side by side.