This is the 3489th most frequent Russian word.
работающим
"Работающим" means "to the working one" or "to the one who is working" (dative case, singular).
Here, 'работающим' is used in an instrumental case to describe the printing press as 'functioning'.
Она поговорила с работающим печатным станком.
She spoke with the functioning printing press.
In this sentence, 'работающим' is in the dative case, referring to people working with the new equipment.
Сотрудники помогли работающим на новом оборудовании.
The employees helped those working on the new equipment.
Here, 'работающим' is modified to the accusative case to describe the driver who is working.