Most major coal-hauling Class I railroads have held onto velocity gains made this year. The major US railroads' average coal train speed, when measured on a rolling four-week basis, has increased over 2011. The two Canadian carriers experienced a drop in coal train velocity.
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机译：名称：激光绑带蝙蝠速度训练器。描述：用臀部而不是上身（肩膀和手臂）摆动，可以提高击球速度。使用我们的Laser Strap Bat Speed Trainer时，如果您的上半身摇摆，则会导致地面球变弱，弹出或摇摆而丢失。激光绑带蝙蝠速度训练器可以将肘部紧贴身体，帮助您的核心保持与挥杆的连接。改善双手的上挥杆动作对于提高力量至关重要。
