At 15 mph, which switch size can be traversed?

At 15 mph, which switch size can be traversed?

• A. 6 switch
• B. 12 switch
• C. 20 switch
• D. 8 & 10 switch

Answer: (D)

Traversing a switch safely depends on the switch’s speed rating. For a train moving at 15 mph, you must use a switch size that is rated to handle at least that speed. In the SMT-1 context, the mid-range switch sizes have a published rating that includes 15 mph, so they can be traversed at that speed. Other switch sizes either have a lower rating or are intended for different operating conditions, making them unsuitable for crossing at 15 mph. So the option that lists the mid-range switch sizes is the correct choice because those sizes meet the 15 mph requirement.

Traversing a switch safely depends on the switch’s speed rating. For a train moving at 15 mph, you must use a switch size that is rated to handle at least that speed. In the SMT-1 context, the mid-range switch sizes have a published rating that includes 15 mph, so they can be traversed at that speed. Other switch sizes either have a lower rating or are intended for different operating conditions, making them unsuitable for crossing at 15 mph. So the option that lists the mid-range switch sizes is the correct choice because those sizes meet the 15 mph requirement.