I'm doing triple the work in less than half the time

So my job kind of sucks. I worked here a year and doing triple the work in half the time. They constantly have me training the other departments but refuse to promote me. So I asked for less days in the office and it's been granted. I'm not invested because there no way to promote and I already doing triple my work load. At this point would asking for a raise be fair? I hoped that I'd get promoted but that seems impossible. They also won't let me auctully work in other departments despite having me train the other departments. Which training shouldn't be part of my job cuase it's a waste of my time. The managers and lead are supposed to be training and I'm not paid or treated like a lead. So I don't feel like that's my job. The job also maxs out at 30 hours.