With no explanation, label each line with "O", "product-train", "art-broadcastprogram", "art-film", "art-music", "art-other", "art-painting", "art-writtenart", "building-airport" or "building-hospital" preceded by ":".
The
SD50
was
in
many
respects
a
transitional
model
between
EMD
's
Dash
2
series
which
was
produced
throughout
the
1970s
and
the
microprocessor-equipped
SD60
and
SD70
locomotives
.
The:O
SD50:product-train
was:O
in:O
many:O
respects:O
a:O
transitional:O
model:O
between:O
EMD:product-train
's:product-train
Dash:product-train
2:product-train
series:O
which:O
was:O
produced:O
throughout:O
the:O
1970s:O
and:O
the:O
microprocessor-equipped:O
SD60:product-train
and:O
SD70:product-train
locomotives:O
.:O