gistfile1.js

var move = function(value, inner){
  var h = (inner.getHeight() - inner.up('div').getHeight());
  inner.style.top = (Math.round(value * h) * -1) + 'px';
}

var setup = function(thumb, track, inner, plus = null, minus = null){
  var s = new Control.Slider(thumb,track, {
    axis:'vertical',
    onChange: function(value){
      move(value, inner);
    },
    onSlide: function(value){
      move(value, inner)
    }
  });
  if(!!plus){
    $(plus).observe(
      'click',
      function(evt){
        s.setValue(s.value < 1 ? s.value + 0.1 : 1);
      }
    };
  )
  if(!!minus){
    $(minus).observe(
      'click',
      function(evt){
        s.setValue(s.value > 0 ? s.value - 0.1 : 0);
      }
    );
  }
}

setup('slide1thumb', 'slide1track', 'slide1inner', 'plus1', 'minus1');
setup('slide2thumb', 'slide2track', 'slide2inner', 'plus2', 'minus2');
setup('slide3thumb', 'slide3track', 'slide3inner', 'plus3', 'minus3');