Re: Caboose - 0313 grab irons

They are where the Feds have always specified they should be, see below, from the FRA's web site. I would say the curved shape is to help a person board when the caboose is sailing past at a fairly high speed.
TITLE 49--TRANSPORTATION
CHAPTER II--FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF
TRANSPORTATION
PART 231--RAILROAD SAFETY APPLIANCE STANDARDS--Table of Contents
Sec. 231.10 Caboose cars with platforms.
(f) Side handholds--(1) Number. Four.
(2) Dimensions. Minimum diameter, five-eighths of an inch, wrought
iron or steel. Minimum clear length, 36 inches. Minimum clearance, 2,
preferably 21/2, inches.
(3) Location. (i) One near each end on each side of car, curving
downward toward center of car from a point not less than 30 inches above
platform to a point not more than 8 inches from bottom of car. Top end
of handhold shall be not more than 8 inches from outside face of end
sheathing.