Drain channeling

On 1940's/50's basement slab, we often find 2 or 3" max of concrete on the basement slab - pretty easy to cut and channel for new drains.  We have elected to replace the entire drain system, as what we had to work with was simply not up to snuff.  However, the concrete is 4"-5" thick, and takes quite a lot of work.  Rocco has been cutting channels for almost two days, and we're now smashing and chipping our way before the plumbers arrive.