rail bound manganese steel frog

例句：

1. 1.The railway used manganese steel frogs to protect the tracks from damage.
   铁路使用锰钢铸型青蛙来保护轨道免受损坏。
2. 2.The engineer designed the manganese steel frogs to ensure smooth operation of the train.
   工程师设计了锰钢铸型青蛙，以确保火车的平稳运行。
3. 3.The manganese steel frogs were a significant investment in the construction of the railway.
   锰钢铸型青蛙是铁路建设的重要投资。