diff --git a/src/main/java/org/opentripplanner/apis/transmodel/model/stop/QuayType.java b/src/main/java/org/opentripplanner/apis/transmodel/model/stop/QuayType.java
index 7e51328e88f..e146b537c1c 100644
--- a/src/main/java/org/opentripplanner/apis/transmodel/model/stop/QuayType.java
+++ b/src/main/java/org/opentripplanner/apis/transmodel/model/stop/QuayType.java
@@ -216,6 +216,9 @@ public static GraphQLObjectType create(
             GraphQLArgument
               .newArgument()
               .name("timeRange")
+              .description(
+                "Duration in seconds from start time to search forward for estimated calls. Must be a positive value. Default value is 24 hours"
+              )
               .type(Scalars.GraphQLInt)
               .defaultValue(24 * 60 * 60)
               .build()
diff --git a/src/main/java/org/opentripplanner/apis/transmodel/model/stop/StopPlaceType.java b/src/main/java/org/opentripplanner/apis/transmodel/model/stop/StopPlaceType.java
index 3ab444bb52c..13a1521bf1a 100644
--- a/src/main/java/org/opentripplanner/apis/transmodel/model/stop/StopPlaceType.java
+++ b/src/main/java/org/opentripplanner/apis/transmodel/model/stop/StopPlaceType.java
@@ -290,6 +290,9 @@ public static GraphQLObjectType create(
             GraphQLArgument
               .newArgument()
               .name("timeRange")
+              .description(
+                "Duration in seconds from start time to search forward for estimated calls. Must be a positive value. Default value is 24 hours"
+              )
               .type(Scalars.GraphQLInt)
               .defaultValue(24 * 60 * 60)
               .build()
diff --git a/src/main/resources/org/opentripplanner/apis/transmodel/schema.graphql b/src/main/resources/org/opentripplanner/apis/transmodel/schema.graphql
index d263667d672..e6f4208c643 100644
--- a/src/main/resources/org/opentripplanner/apis/transmodel/schema.graphql
+++ b/src/main/resources/org/opentripplanner/apis/transmodel/schema.graphql
@@ -571,6 +571,7 @@ type Quay implements PlaceInterface {
     omitNonBoarding: Boolean = false @deprecated(reason : "Non-functional. Use arrivalDeparture instead."),
     "DateTime for when to fetch estimated calls from. Default value is current time"
     startTime: DateTime,
+    "Duration in seconds from start time to search forward for estimated calls. Must be a positive value. Default value is 24 hours"
     timeRange: Int = 86400,
     "Parameters for indicating the only authorities and/or lines or quays to list estimatedCalls for"
     whiteListed: InputWhiteListed,
@@ -1132,6 +1133,7 @@ type StopPlace implements PlaceInterface {
     numberOfDeparturesPerLineAndDestinationDisplay: Int,
     "DateTime for when to fetch estimated calls from. Default value is current time"
     startTime: DateTime,
+    "Duration in seconds from start time to search forward for estimated calls. Must be a positive value. Default value is 24 hours"
     timeRange: Int = 86400,
     "Parameters for indicating the only authorities and/or lines or quays to list estimatedCalls for"
     whiteListed: InputWhiteListed,