For childcare outside of normal work hours it's probably going to be family, friends, or a full-time nanny. We used family and friends but only needed them when my wife's occasional travel overlapped my trips, once every couple of months.

You can't rely on ad-hoc babysitters, so a nanny may be the only other solution. You could explore in-home daycare... maybe somebody would do it after hours.

I have heard of after-hours childcare at large factories which do shift work, and in factory towns.