Equal height columns is the default behaviour for Bootstrap 4 grids.
.col { background: red; }_x000D_
.col:nth-child(odd) { background: yellow; }
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<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-alpha.6/css/bootstrap.min.css" integrity="sha384-rwoIResjU2yc3z8GV/NPeZWAv56rSmLldC3R/AZzGRnGxQQKnKkoFVhFQhNUwEyJ" crossorigin="anonymous">_x000D_
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<div class="container">_x000D_
<div class="row">_x000D_
<div class="col">_x000D_
1 of 3_x000D_
</div>_x000D_
<div class="col">_x000D_
1 of 3_x000D_
<br>_x000D_
Line 2_x000D_
<br>_x000D_
Line 3_x000D_
</div>_x000D_
<div class="col">_x000D_
1 of 3_x000D_
</div>_x000D_
</div>_x000D_
</div>
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