Complex sentence: LP cylinder volume ratio has to be carefully determined, usually by increasing the LP cylinder diameter and/or by lengthening the stroke; on geared locomotives, cylinder volumes can be kept more or less identical by increasing LP piston speed.
Split into simpler sentences: LP cylinder volume ratio has to be carefully determined, usually by increasing the LP cylinder diameter and/or by lengthening the stroke. On geared locomotives, cylinder volumes can be kept more or less identical by increasing LP piston speed.