~/simutrans.dev/pak128.Britain$ svn diff
Index: boats/diesel-barge.dat
===================================================================
--- boats/diesel-barge.dat (revision 1833)
+++ boats/diesel-barge.dat (working copy)
@@ -244,7 +244,7 @@
name=DieselBargeOil
copyright=Jamespetts
waytype=water
-engine_type=steam
+engine_type=diesel
smoke=Diesel
speed=11
power=50
@@ -336,4 +336,4 @@
FreightImage[0][N]=./images/diesel-barge-light-cover.1.2
FreightImage[0][NE]=./images/diesel-barge-light-cover.1.3
----
\ No newline at end of file
+---
Thank you for the report - fixed in the Experimental version.