diff --git a/DESCRIPTION b/DESCRIPTION
index 6b789eb..12dbdc8 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -1,6 +1,6 @@
 Package: m4ra
 Title: Many-to-Many Multi-Modal Routing Aggregator
-Version: 0.1.1.024
+Version: 0.1.1.025
 Authors@R: 
     person(given = "Mark",
            family = "Padgham",
diff --git a/R/gtfs.R b/R/gtfs.R
index 0c21698..9daa6ad 100644
--- a/R/gtfs.R
+++ b/R/gtfs.R
@@ -169,10 +169,11 @@ gtfs_next_intervals <- function (gtfs, stops, res, start_time_limits) {
         start_times,
         diff (start_time_limits)
     )
+    next_starts [next_starts <= 0] <- NA_integer_
 
     first_starts <- lapply (res, function (i) as.vector (i [, 1]))
     first_starts <- do.call (rbind, first_starts)
-    first_starts [first_starts == .Machine$integer.max] <- NA_integer_
+    first_starts [first_starts == .Machine$integer.max | first_starts <= 0] <- NA_integer_
     next_interval <- next_starts - first_starts
 
     # diagonals set in prepare-data routines:
diff --git a/codemeta.json b/codemeta.json
index 7afb174..aefb9ac 100644
--- a/codemeta.json
+++ b/codemeta.json
@@ -7,7 +7,7 @@
   "codeRepository": "https://github.com/UrbanAnalyst/m4ra",
   "issueTracker": "https://github.com/UrbanAnalyst/m4ra/issues",
   "license": "https://spdx.org/licenses/GPL-3.0",
-  "version": "0.1.1.024",
+  "version": "0.1.1.025",
   "programmingLanguage": {
     "@type": "ComputerLanguage",
     "name": "R",