It reads "Sakura Traffic Park" or the traffic park in the Sakura area
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There is a park in my city where kids can learn the traffic rules. This park is called "Sakura Traffic Park" and it also displays a very old Japanese steam locomotive, D5170.
It was manufactured by Hitachi in September '37. And the total distance this locomotive covered was close to 3 million kilometers, which translates into 4 times the length between the earth and the moon.
As you know "D" is the fourth alphabet, so the "D" in D5170 means the locomotive is a 4-wheel drive. People used to pay attention to how fast it ran, but this D5170 had excellence in its towing force and was used for towing freight trains. In comparison a locomotive whose name starts with the third alphabet "C" was a 3-wheel drive and towed passenger cars, which required less power.
I think among retired Japanese trains this D5170 is the most popular among the Japanese kids and railroad buffs.