MakePipe behaving oddly

In the attached scripts I create an object by extruding along a wire. You can see it's a railway rail. I need the cross-sections to remain normal to the wire so I've used MakePipe. Script t011a uses a wire made from a line and an arc and is OK. Version t011b uses a wire made from 3 lines but is not OK because the cross-section does not stay normal. Why?

Sorry, there are no files attached.

I've tried to create an object by extruding a profile along a wire. I need the cross-sections to remain normal to the wire so I've used MakePipe. Version (a) uses a wire made from a line and an arc and is OK. Version (b) uses a wire made from 3 line segments but the cross-section doesn't remain normal to the wire. Why?

The python scripts include the following:

vector1 = geompy.MakeVector(p0,p1)
vector2 = geompy.MakeVector(p1,p2)
vector3 = geompy.MakeVector(p2,p3)
arc1 = geompy.MakeArc(p1,p2,p3)

script a):
wire1 = geompy.MakeWire([vector1,arc1])

script b):
wire1 = geompy.MakeWire([vector1,vector2,vector3])

then ...
solid1 = geompy.MakePipe(profile1,wire1)

Attempted to add the attachments again but they wouldn't. Only figures, possibly not needed anyway.

Hello Andy,
I think your problem is related to a sharp corner between two edges.
Try to use Fillet_1D with a small radius in order to have a smooth path. This should work.

If this solution is doesn't fit your needs you could try to make two distinct extrusions and the fuse the created shapes.

Best regards,
Richard